Help with track lighting decision

I asked a question about replacing my MR16 track lights for eye wear displays in my office last year. I still haven’t done anything and my fixtures are croaking so I need to replace them with something but the more I research I do, the more confused I get.

Most of the native LED track fixtures I’ve found have been very expensive and/or I couldn’t find the CRI on them and I need high CRI. So… if I’m starting from scratch and my desire is to convert to LED, is there any advantage of MR16 vs PAR 20 vs PAR 30? And is any particular fixture type better for LED? I was thinking a gimbal might be better assuming the bulb fits the fixture because it is more open. Or should I just get a few replacement MR 16 fixtures and keep the halogen for now and wait for better options?