What mattb says, all to do with toe, antisquat is done with the spacers under the blocks.
As Matt says, tell us a bit more about the track your running on and we will do our best to get you in the ball park
As for the gearing which motor is it your using? I run 21/78 on a 5.5, 23 or 24 / 78 on a 6.5 and 27 or 28 on an 8.5 ... guessing a 7.5 would go in at about 25 ish.
My motors are Speed Passion V3.0 and I'm quite easy on motors so can gear higher than some.
Hope that helps.