That’s kinda hard to answer. It really depends on the target’s defence, crit resistance, and your critical rate from equips. Here’s a few things to note, if min-maxing is what you’re aiming for.
Disclaimer: The exact interaction between running shot and criticals is still a little unclear at this point, so take my auto attack advice with a pinch of salt. I don’t have a quarrel shooter to test, and haven’t seen anyone confirm if running shot’s multiplier is applied after elemental damage and/or crit attack. Someone has even reported to have found that running shot causes a double application of the ‘critical attack’ stat. https://forum.treeofsavior.com/t/is-the-critical-attack-x2-while-running-shot/249430
I’ll just go by the principle of parsimony and take the simplest calculation (running shot applied first, right after attack stats are summed) for this answer.
When it comes to running shot auto attacks, the didel grandcross + manamana combo beats musket damage. You’d only switch to musket to cast attack skills, which means only swift step’s crit should be factored in for musket calculations; no kneeling shot.
Since you’ve got swift step and kneeling shot to multiply your crit rate during your crossbow + running shot duration, optimising your auto attack damage would basically involve aiming to just barely hit 100% crit chance, or as close as you can get it to 100% with your equips and DEX. Leftover points go to STR. Dex is prioritised because each point of crit rate is now worth more (multiplied by the attributes), and especially because your effective attack gets increased by dex which, when multiplied by running shot’s x3 to x4.2, is sufficiently large for crit rate to give greater returns than increments of attack.
Best musket skill damage is similar. Focusing on snipe damage for that quick burst of dps, your effective attack is bundled with snipe’s 5997 skill attack before going through the crit multiplier. In this situation, critical rate from DEX is worth far more than additional attack from STR, even with the 70% bonus in STR stat points taken into account.
About that 4501 total attack before crit at end game, it’s unlikely. Even with great gear, you’d probably only be in the 1100 - 1300 range with a full STR build. When added to big hitters like the musketeer skills though, the total can easily exceed 4501, so that’s something to consider. Full DEX is good for musketeers because of their high attack skills. Non-kneeling non-running auto attacks from a 400 attack gun doesn’t provide enough effective attack to warrant a full DEX build.
Here’s the TLDR of it. Assuming you’re able to get some good endgame gear, i.e. upgrade your didel grandcross and finisher to +10, get a manamana, use lvl 7 crit gems on your weapons, running shot gem on armour, double sissel, 33 att headgear x3, etc. these are some rough stat spreads you might want to aim for. Points are spared for other stats since you might want to invest in some CON.
For auto attacks vs. a 457 def 120 crit resist target (the average world boss?),
0 points in other stats: 0.61 STR per point in DEX
25 points in other stats: 0.49 STR per point in DEX
50 points in other stats: 0.36 STR per point in DEX
75 points in other stats: 0.22 STR per point in DEX
100 points in other stats: 0.1 STR per point in DEX
For musket snipe damage vs. a 457 def 120 crit resist target,
0 points in other stats: 0.28 STR per point in DEX
25 points in other stats: 0.17 STR per point in DEX
50 points in other stats: 0.07 STR per point in DEX
75+ points in other stats: Full DEX
Yeah…you could aim for either one or somewhere in between.
*If running shot’s multiplier is applied after critical attack stat is added, then the optimum stat spreads for auto attack crossbow (prioritise STR in a 1.5~2.5 STR per point in DEX ratio) and skill burst musket (prioritise DEX in a 0.3~0 STR per point in DEX ratio) would be in conflict. Just decide if you want to focus on your burst or sustained dps in that case.