Re: 45 host
The best 45 host in my opinion is an HK, next is a Glock, next is a Sig 220. Get the brand and model that fits you best.
I used to have a USP 45 and HK45Compact. I now have the full size HK45. All are super reliable and for me the best suppressed platform for the 45 cal round. I did not notice a lot of functional difference between the HK models, just the grip and ergonomics.
I have had all of the generations of the Glock 21. I now have a Gen3SF and it is the best fit for my hand of the Glock models.
I have had a number of 220s and the Combat is very good. I have had a few other 220s with threaded barrels but they can be a bit picky at times.
I have not shot the FN but it seems interesting and holds a lot of ammo.
I have tried a few other brands and cannot recommend them.