The input I have heard is when burning alky, there is no improvement running collectors. I would suggest 1 5/8", again no improvement in length , mine are only 12" from head to tip. Zoomies make less power when burning gasoline. Problem is finding a dyno that can test with zoomies. Because of noise and alky fumes, you would have to find a dyno that can test outside, but you'll still have a noise issue.
Zoomies are the rule with NHRA Heritage Jr Fuel, and they sound Great ! If the pipes are aimed more back then upright you'll get some forward reaction. More upright for more down pressure if you have some mid-track traction issues.
Of course, call me 800-624-3803 about front wire spokes, I'm sure I can come-up with something to fit your budget.
Jon