550’s. how big is to big?

I recently purchased me and my wife both some 2014 model 550’s with EPS (smokin deal is the only reason I bought 2). I won’t be home till late this year,but I am already looking at tires for mine.I already have tire selection out of the way, I’m gonna be getting the executioners. I know alot of people run the 26 or 27 x10 on the front,but I was thinking of going with the 12 wides all the way around, and I’m undecided if I will replace the rims,or stay with stock rims. anyone else running widesall the way around?
Also I know that they are considered a heavy tire, so are 27’s going to be the max that my 550 can handle? Respectivly I do plan on doing the shim mod,and either an orange or purple spring right off the bat. Thanks for any input.