As long as you don't do burnouts all the time (or once with slicks :p ), launch it hard or spin the tires going around a corner your trans will hold up for quite a while.
Mine was at 15 psi daily and has the line pressure maxed due to a bad solenoid inside it and has had no problems whatsoever.
Really all you need is a stronger IS and maybe gearset/chain so save up for that and get one built for when the trans does eventually go, then you are only down 1 day swapping them out.
I'm excited to see this build, it's exactly what I would do if I were to do it all over again and wish I did do from the start. Would have had a much better and more reliable build for less money.