i think what the original poster means to ask is if having decent dex but more stamina or if having more dex and decent stamina makes you swing faster?
=/ It made more sense before you rephrased it.
in short, does having 175/175 stamina make you swing faster than having 150/150 stamina?
...
No, because as I said in the post before yours...
"every 30 stamina takes a tick (0.25s) off"
Take a weapon like... a regular bow. Base speed is 4.25, if you have 30 stamina the delay between swings becomes 4.0, if you have 60 stamina it becomes 3.75, if you have 90 stamina it becomes 3.5 & so on & so on at 120, 150, & 180.
However! It can still be worth having more stamina than necessary to take into account being cursed, movement and taking damage.
No. Dex only affects bandage speed and works in 20's. As the maximum dex is 150, 140 is the last point at which bandage time is reduced (4 seconds).
Edit:
Having re read the OP, Basara said it all really. The origional question was 'is SSI affected by dex or stamina' & the answer is neither it's independant of both.