Frank:
First, let me welcome another 'Jersey Guy' to the ECN forums. I'm close by to you & my e-mail is in my profile.
Mfg catalogs (cut sheets) or specs can give you the info you need. I'm assuming you are going to a supply house, not the 'big-box'??
Remember, if you are talking MR16/MR11 the actual beam spread of the bulbs is important. Also, did you think of the adjustable 'gimbal ring' type recess??
John