this is a first time redoing my brake lines. I am shaving my engine bay and plan on doing a proportional valve tuck. i was wondering what size of hardline should i use. do the left and right hardline have to have equal length? what about the rear. also is it bad to hard to long of a line? or is it better to keep it short as possible?

 

length doesnt really matter. you will have a insignificant pressure difference on a longer line. IIRC honda brakes use standard 5/16" tubing with double inverted flares on 10mmx1.0 compression fittings.