that certainly is the definition of painful! i re-read it one day to see what i went through - amazing how much i had learnt
none whatsoever! brilliant idea make sure the pump is a well respected and reliable brand (eheim, iwaki) also just make sure you use pressure piping for return piping (overflow doesnt matter so much) pressure piping more expensive but worth it for the added strength. also consider adding a backup for the overflow incase one outlet gets blocked (im about to do this to mine soon) like this:
always go bigger for your piping than you anticipate, you can always 'throttle' it back if needed with ball valves. lastly dont underestimate the cost of plumbing!