[Skarg]

Originally Posted by zot

I started this attempt (before looking for old posts) thinking of just subtracting DX but that seemed too extreme.

Yeah, that is too extreme. You'd need to make DX cost twice as much as ST to balance it.

Originally Posted by zot

... Still, the subtraction plus halving seems to me like it'd bog things down. ... I do use TFT as a benchmark for combat speed. Not too many systems are faster in my experience.

System speed is different for different GMs and practice levels. When I've prepared, I can run GURPS combat almost as fast as TFT, and a little math doesn't slow me down much. I require players to tell me what they do when it's their turn to act. A GM who slows down for math, looks up rules during play, struggles with DX order, or lets players waffle during their turn, look up stats or rules, slowly count dice pips, etc, can take massively longer to get through a turn.

So I realize a rule that I can run easily may totally stop other players from using it. Still, I like to develop rules that work the way I want to, and later consider what might be an easy rule for others (unless/until one comes to mind).

Originally Posted by zot

With or without the recorded MOD, modifiers are still getting cut in half.

But the rounding effects are different if you subtract 10, halve and round first, as opposed to comparing DX and then halving and rounding that.

With Chris' compare-later system:

DX 10 attacks DX 10 at 10, and vice versa, of course.
DX 11 attacks DX 10 at 11, and DX 10 attacks DX 11 at 10.
DX 12 attacks DX 10 at 11, and DX 10 attacks DX 12 at 9.
DX 13 attacks DX 10 at 12, and DX 10 attacks DX 13 at 9.

Notice that each increase in DX results in either a +1 to hit or a -1 to opponent's attack. That more or less retains the same sort of balance for DX that the original game has.

With pre-calculated DEF = (DX - 10) / 2 (round up):

DX 10 attacks DX 10 at 10, and vice versa, of course.
DX 11 attacks DX 10 at 11, and DX 10 attacks DX 11 at 9.
DX 12 attacks DX 10 at 12, and DX 10 attacks DX 11 at 9.
DX 13 attacks DX 10 at 13, and DX 10 attacks DX 13 at 8.

Notice that each increase in DX gives you a +1 to hit, but every SECOND increase in DX ALSO gives you a -1 to be hit. So not only is the difference in DX 50% greater than in Chris' system, it's also uneven: increasing adjDX to an odd number is twice as impactful as increasing adjDX to an even number. And so in choosing armor or shield, you'd want to consider that it's better to reduce your adjDX to an odd number than to an even number.