Have a 52# @ 27 Centaur Carbon coming in late July.  I pull 27.5".

Want to shoot 185-200 grain broadheads on 29.5" - 30" shaft with decent FOC.  

I'm a fan of small diameter carbons (Axis, MFX, etc.).

What do you more experienced shooters recommend as far as set-up (shaft/insert/spine)?

400 spine for those weight heads

X2

You may be using a 500 spine shaft with only 200 grains out front at that length. My one piece Tomahawk pulls 54# @ 27.5" and it took a total of 275 grains out front to get a 400 spine shaft in tune.

With heavy inserts you may get away with a 400 but it depends alot of how much centershot you have in the bow as well, less centershot and you need a weaker spined shaft, cut way past center and you can get away with it.  
You are going to be right around the edge with both 500 and 400 spine ranges and really need to get an arrow in each spine to try, that is the only certain way.

I shoot a .400 spined 29.5 out of my Centaur's. The 62"er's arrow is a normal "stock" bushing,with a .175 head. Deadly. The 60"er's arrow is a 50grained bushing,with .225 up frt. You will love the .400 spine arrow. rat'