1/4 mile vs 1/8 mile

I tried 5.13 gears after running 4.86 in both 1/8 & 1/4. 5.13 would have been too much for the 1/4 and I didn't see an ET gain in the 1/8.

Focus on one car and optimize it for the 1/4. Overgearing, even for the 1/8, may hurt consistency, especially when track prep may not be the best. Consistency and predictability wins bracket races, not fastest ET. Racing the same car will help you get it sorted out and familiarized with it much faster & easier. Most of all, you won't be spending twice the money and twice the time to set up two different cars!