How do I test and cut holes contained by shower stall for tap and shower boss? I want replace the fiberglass shower stall in my house. I'm really...

I want replace the fiberglass shower stall in my house. I'm really concerned that I'll cut the holes surrounded by the wrong place and have to buy a investigational one. Any hints on how to avoid that?
Answers:    Measure, then re-measure, next measure everything again. standard to the centers of the pipes, and mark on the panel. Take your measurements from the lip of the tub and the point on the outside top where the panel will bring to a close. Do the math for seams, overlaps and the approaching.

Most importantly TAKE YOUR TIME, its not race. double check not simply the measurements of the pipes, but the marks you hold made on the panel. Resist the urge to use the old lipstick on the pipe/press the panel against it trick, this seldom works.

IF you have further question please feel free to ask.
If the dated piping is still there and it is slightly proud of the wall, a trick I hold used is to coat the old piping near lipstick, place the stall in place temporarily, and verbs the imprint to the new shower stall, remove and do your adjectives