the inspector shows BlendShape names but SkinnedMeshRenderer doesn't let me talk to it using them, makes me irate

SkinnedMeshRendererExtensions.cs

using System;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// For working with SkinnedMeshRenderer without failing silently or dealing with age old Unity decisions that were
/// <a href="https://forum.unity.com/threads/removing-clamping-of-blendshapes-to-the-range-0-100.504973/">never fully undone</a>.
/// </summary>
/// 
public static class SkinnedMeshRendererExtensions {
	[Flags]
	public enum SafeSkinnedMeshRendererAccessModes {
		/// <summary>
		/// LogError or return silent bad values like Unity does by default.
		/// </summary>
		None = 0,
		/// <summary>
		/// Prevents bad Unity behaviors like untracable LogWarnings or silent failure and allows you to catch errors if anything unexpected occurs.
		/// </summary>
		Safe = 1,
		/// <summary>
		/// When Unity imports models, it expects BlendShape values between [0,1] and then scales their value to [0,100] unless you change it on the prefab.
		/// Effectively, you have to supply a BlendShape weight of 100f to get similar results to having that BlendShape set to 1f in Blender.
		/// NOTE: These methods won't work on animated values, unfortunately.
		///  
		/// When you supply this flag:
		/// * All reads from the BlendShape will be divided by 100.
		/// * All writes to the BlendShape will be multiplied by 100.
		/// * This means you will instead be supplying values between [0f,1f].
		/// </summary>
		Scale100 = 2,
	}

	/// <summary>
	/// Get BlendShape Weight by name with an exception and scaling.
	/// Without the "Safe" flag, Unity will return "0" silently. With it, an IndexOutOfRangeException is thrown.
	/// Additionally, a KeyNotFoundException will occur if there is no BlendShape by that name.
	/// </summary>
	/// <param name="smr"></param>
	/// <param name="shapeName"></param>
	/// <param name="value"></param>
	/// <param name="mode"></param>
	/// <returns></returns>
	/// <exception cref="KeyNotFoundException"></exception>
	public static float GetBlendShapeWeightByName(this SkinnedMeshRenderer smr, string shapeName, float value, SafeSkinnedMeshRendererAccessModes mode = SafeSkinnedMeshRendererAccessModes.Safe) {
		int index = smr.sharedMesh.GetBlendShapeIndex(shapeName);
		if (index == -1 && mode.HasFlag(SafeSkinnedMeshRendererAccessModes.Safe)) {
			throw new KeyNotFoundException($"BlendShape by name \"{shapeName}\" did not exit on mesh.");
		}
		return smr.GetBlendShapeWeightSafe(index, mode);
	}

	/// <summary>
	/// Set BlendShape Weight by name with an exception and scaling.
	/// Without the "Safe" flag, Unity causes a LogError without a stack trace. With it, an IndexOutOfRangeException is thrown.
	/// Additionally, a KeyNotFoundException will occur if there is no BlendShape by that name.
	/// </summary>
	/// <param name="smr"></param>
	/// <param name="shapeName"></param>
	/// <param name="value"></param>
	/// <param name="mode"></param>
	/// <exception cref="KeyNotFoundException"></exception>
	public static void SetBlendShapeWeightByName(this SkinnedMeshRenderer smr, string shapeName, float value, SafeSkinnedMeshRendererAccessModes mode = SafeSkinnedMeshRendererAccessModes.Safe) {
		int index = smr.sharedMesh.GetBlendShapeIndex(shapeName);
		if (index == -1 && mode.HasFlag(SafeSkinnedMeshRendererAccessModes.Safe)) {
			throw new KeyNotFoundException($"BlendShape by name \"{shapeName}\" did not exit on mesh.");
		}
		smr.SetBlendShapeWeightSafe(index, value, mode);
	}
	
	/// <summary>
	/// Get BlendShape Weight with an exception and scaling.
	/// Without the "Safe" flag, Unity will return "0" silently. With it, an IndexOutOfRangeException is thrown.
	/// </summary>
	/// <param name="smr"></param>
	/// <param name="index"></param>
	/// <returns></returns>
	/// <exception cref="IndexOutOfRangeException"></exception>
	public static float GetBlendShapeWeightSafe(this SkinnedMeshRenderer smr, int index, SafeSkinnedMeshRendererAccessModes mode = SafeSkinnedMeshRendererAccessModes.Safe) {
		int shapeCount = smr.sharedMesh.blendShapeCount;
		if (mode.HasFlag(SafeSkinnedMeshRendererAccessModes.Safe)) {
			if (shapeCount == 0) {
				throw new IndexOutOfRangeException("Cannot get BlendShape weight for mesh with zero BlendShapes.");
			}

			if (index < 0 || index >= shapeCount) {
				throw new IndexOutOfRangeException(
					$"Cannot get BlendShape weight index {index} for mesh, valid range is: [0,{shapeCount - 1}].");
			}
		}

		float value = smr.GetBlendShapeWeight(index);
		
		if (mode.HasFlag(SafeSkinnedMeshRendererAccessModes.Scale100)) {
			value /= 100f;
		}

		return value;
	}

	/// <summary>
	/// Set BlendShape Weight with an exception and scaling.
	/// Without the "Safe" flag, Unity causes a LogError without a stack trace. With it, an IndexOutOfRangeException is thrown.
	/// </summary>
	/// <param name="smr"></param>
	/// <param name="index"></param>
	/// <param name="value"></param>
	/// <param name="mode"></param>
	/// <exception cref="IndexOutOfRangeException"></exception>
	public static void SetBlendShapeWeightSafe(this SkinnedMeshRenderer smr, int index, float value, SafeSkinnedMeshRendererAccessModes mode = SafeSkinnedMeshRendererAccessModes.Safe ) {
		int shapeCount = smr.sharedMesh.blendShapeCount;
		if (mode.HasFlag(SafeSkinnedMeshRendererAccessModes.Safe)) {
			if (shapeCount == 0) {
				throw new IndexOutOfRangeException("Cannot set BlendShape weight for mesh with zero BlendShapes.");
			}

			if (index < 0 || index >= shapeCount) {
				throw new IndexOutOfRangeException(
					$"Cannot set BlendShape weight index {index} for mesh, valid range is: [0,{shapeCount - 1}].");
			}
		}

		if (mode.HasFlag(SafeSkinnedMeshRendererAccessModes.Scale100)) {
			value *= 100f;
		}

		smr.SetBlendShapeWeight(index, value);
	}
}