Marksman or Bowmaster

Keep in mind that Snipe --> Strafe macros have no real drawbacks to them. You can keep using that and it'll just tell you "The skill is not ready!" until the 10 seconds are up.

At least, I think... I'm not a marksman yet so I can't verify that

I can verify that. I suggested that to a guildy and he did a strafe-snipe-strafe macro which did snipe at max speed.

BUT, you must remember the actual shot.
Each strafe is .72 second, each snipe is .72 seconds with 10 second inbetween. This means that there won't be an even number of strafes to fit 10 seconds.

First the snipe would be fired, so as soon as strafe is eligible fire, you're in .72s into the 10s cooldown time (9.28s left)
13 strafes is the closest number of strafes possible to allow another snipe.
This puts the total time now at 9.36+.72 = 10.08 seconds.

So 1 snipe and 13 strafes cycle is 10.08 seconds at maximum fire rate (with a macro). You may want to reconsider that in your calcs (as it would be closer to 10 seconds).

EDIT: I'm still having trouble matching your base calcs, tell me what I'm doing wrong:
{ [ (4897+5999)/2 * (1+2.4*.55)*4 ] } / .72
60/(83+1/3) = .72 O_o
Can't figure it out, that should be strafe base DPS 4897~5999.