gp.js

const MAXGP = 800;
const MAXSECONDS = 3600;
const CORDIALGP = 300, HQCORDIALGP = 350, HICORDIALGP = 400;
const CORDIALCD = 240, HQCORDIALCD = 216, HICORDIALCD = 180;

function fullGP (potGP, potMaxCD) {
    var seconds = 0;
    var potCD = 0;
    var potsUsed = 0;
    var gp = 800;
    var collected = 0;
    while (seconds < MAXSECONDS) {
        if (gp == 800) {
            // GP is maxed, so collect
            seconds += 30;
            potCD -= 30;
            gp = 0;
            collected += 3;
        } else if (800 - gp >= potGP && potCD == 0) {
            // Potion is off cooldown and nothing will be wasted, use it
            gp += potGP;
            potCD = potMaxCD;
            potsUsed += 1;
        } else {
            // Nothing happens, tick
            gp += 6;
            seconds += 3;
            potCD -= 3;
        }

        if (potCD < 0) {
            potCD = 0;
        }
        if (gp > MAXGP) {
            gp = MAXGP;
        }
    }
    console.log("%ds: %d collected, %d pots used", seconds, collected, potsUsed);
}

function partGP (potGP, potMaxCD) {
    var seconds = 0;
    var potCD = 0;
    var potsUsed = 0;
    var gp = 800;
    var collected = 0;
    while (seconds < MAXSECONDS) {
        if (gp >= 600) {
            // GP is 600 or higher, collect
            seconds += 30;
            potCD -= 30;
            gp -= 600;
            collected += 2;
        } else if (800 - gp >= potGP && potCD == 0) {
            // Potion is off cooldown and nothing will be wasted, use it
            gp += potGP;
            potCD = potMaxCD;
            potsUsed += 1;
        } else {
            // Nothing happens, tick
            gp += 6;
            seconds += 3;
            potCD -= 3;
        }

        if (potCD < 0) {
            potCD = 0;
        }
        if (gp > MAXGP) {
            gp = MAXGP;
        }
    }
    console.log("%ds: %d collected, %d pots used", seconds, collected, potsUsed);
}

console.log("800 GP, NQ Cordials:");
fullGP(CORDIALGP, CORDIALCD);
console.log("800 GP, HQ Cordials:");
fullGP(HQCORDIALGP, HQCORDIALCD);
console.log("800 GP, Hi-Cordials:");
fullGP(HICORDIALGP, HICORDIALCD);

console.log("600 GP, NQ Cordials:");
partGP(CORDIALGP, CORDIALCD);
console.log("600 GP, HQ Cordials:");
partGP(HQCORDIALGP, HQCORDIALCD);
console.log("600 GP, Hi-Cordials:");
partGP(HICORDIALGP, HICORDIALCD);

output.txt

800 GP, NQ Cordials:
3600s: 39 collected, 13 pots used
800 GP, HQ Cordials:
3600s: 45 collected, 14 pots used
800 GP, Hi-Cordials:
3600s: 48 collected, 16 pots used
600 GP, NQ Cordials:
3621s: 38 collected, 15 pots used
600 GP, HQ Cordials:
3600s: 40 collected, 16 pots used
600 GP, Hi-Cordials:
3600s: 46 collected, 18 pots used