LINQPad version for searching static encounter spreads.

LA Static Encounter Calculator.cs

// Global settings to make things easier.

// Set these values for your gender ratio:
//    Fixed gender = -1
//     50 M : 50 F = 127
//     25 M : 75 F = 191
//     75 M : 25 F = 63
// 87.5 M : 12.5 F = 31
// Litleo line doesn't exist in LA so we can ignore the last case.
int GenderCompare = -1;

int FlawlessIVs = 3;

void Main()
{
    // Initial state
    string ram = "E1CEA3FF1E3A9B5CB709ACB78FF71808";
    string str0 = ram.Substring(16).Trim();
    string str1 =  ram.Substring(0, 16);
    ulong s0 = Convert.ToUInt64(str0, 16);
    ulong s1 = Convert.ToUInt64(str1, 16);

    // Set this for how far you want to search.
    int maxAdvance = 1_000_000;

	Console.WriteLine(" Adv   | s0               | s1               | EC       | PID      | IVs               | A | G | Nature\n-------+------------------+------------------+----------+----------+-------------------+---+---+-----------");
    var rng = new Xoroshiro128Plus(s0, s1);
    for (int advances = 0; advances < maxAdvance; advances++)
    {
        GetStateStatic(advances, rng);
        rng.Next();
    }
}

// You can define other methods, fields, classes and namespaces here
private void GetStateStatic(int advance, Xoroshiro128Plus rng)
{
    var (s0, s1) = rng.GetState();
    var output = $"{advance, 6} | {s0:x16} | {s1:x16} |";

    var ec = rng.NextInt();
    output += $" {ec:x8} |";

    var fakeTID = rng.NextInt();
    bool isShiny = false;

    var pid = rng.NextInt();

    var ShinyXor = GetShinyXor((uint)pid, (uint)fakeTID);
    isShiny = ShinyXor < 16;
    if (isShiny)
        pid ^= 1000_0000; // antishiny

    output += $" {pid:x8}";

    Span<int> ivs = stackalloc[] { -1, -1, -1, -1, -1, -1 };
    const int MAX = 31;
    for (int i = 0; i < FlawlessIVs; i++)
    {
        int index;
        do { index = (int)rng.NextInt(6); }
        while (ivs[index] != -1);

        ivs[index] = MAX;
    }

    var ivstring = "";
    for (int i = 0; i < ivs.Length; i++)
    {
        if (ivs[i] == -1)
            ivs[i] = (int)rng.NextInt(32);
        ivstring += $"{ivs[i], 2}";
        if (i < 5)
            ivstring += "/";
    }
    output += $" | {ivstring}";

	var ability = rng.NextInt(2);
    output += $" | {ability}";

    var genderchar = "-";
    if (GenderCompare != -1)
    {
        var genderval = rng.NextInt(253) + 1;
        if ((int)genderval < GenderCompare)
            genderchar = "F";
        else
            genderchar = "M";
    }
    output += $" | {genderchar}";
    
    var nature = (int)rng.NextInt(25);
    output += $" | {GameInfo.GetStrings(1).Natures[nature]}";

    // Height/weight are not generated for static encounters.

    // Add your filters here.
    if (nature != (int)Nature.Timid)
        return;
    //if (genderchar != "M")
    //    return;
    //if (ivs[0] != 31 || ivs[1] != 0 || ivs[2] != 31 || ivs[3] != 31 || ivs[4] != 31 || ivs[5] != 31)
    //    return;
	
    Console.WriteLine(output);
}

private static bool GetIsShiny(int tid, int sid, uint pid)
{
    return GetShinyXor(pid, (uint)((sid << 16) | tid)) < 16;
}

private static uint GetShinyXor(uint pid, uint oid)
{
    var xor = pid ^ oid;
    return (xor ^ (xor >> 16)) & 0xFFFF;
}

Setup is:

1. Download/install LINQPad 7.
2. Download dev build PKHeX.
3. Press F4 in LINQPad and add PKHeX.Core.dll to first tab, and PKHeX.Core to second tab,
4. Change the language at the top to C# program, then copy/paste the script in verbatim.
5. Edit your param (seeds, advances, and filters).
6. Click run. Each line should be showing Advances, s0, s1, EC, PID, IVs, Nature.

This is just a working script until someone decides to make something better.