The adventure of the 125gal tank

ok so the stand it done and painted now I have decided to get the tank drilled and use a sump I musta measured the tank wrong and I have since found out it is 112gal. Its measurements are 72'' x 20'' x 18''. SO I am wondering how I go about getting this drilled I am not wanting to really have to drag the tank out of the house to have this done but if need be I will do it. So I guess my question is what size sump on a main floor of an older house would work? I was thinking a 45 gal tank. I want to make a fuge inside the sumb. SO anyone have any suggestions on how I go about doing this? I have NO IDEA when it comes to sumps and how to do them properly. I have so much to buy and not even sure where to start lol. I know I need some new powerheads not sure how many to go with, I need a good skimmer heaters, lights but I think I am going with the aquatic life 72'' 12x39w T5HO. I am not sure what else I need or should get so again any help is welcome.