Welcome to the site!

You're in good company here, whatever plans you had for expenses besides big game hunts and fine rifles are in jeopardy though...

On the rifle.
First thing to note is that you're not going to be sighting that big bore rifle in off the bench -- in what traditional sense you've come to expect.
Big bore Dangerous Game rifles are sighted in and practice shot from field hunting positions - standing, sitting, improvised support from trees and sticks...

What you've been seeing with sling swivels on the barrel is a design premise you'd very much come to appreciate the first time a stock mounted sling swivel tore your hand up under recoil.
The big bore DG rifle is a recoil machine.
From field positions, properly handled, in real hunting scenarios, you'll never notice the recoil, as in the nature of the moment your body and nervous system essentially shield you from the affect of firing the rifle.
Most guys note that the muzzle blast doesn't even seem to effect their hearing, even the very moment after the shot.
What's important is to practice a lot so that your muscle memory is programmed to do the right thing when the dung hits the fan.

On accuracy.., although the Dangerous Game rifle is not designed to be a sub-MOA tack driving long range system, it's surprising to see how many MOA big bore DG rifles you see - even with their express sights, sling swivels and slings present.
I've shot numerous MOA groups over the iron sights of my .458win Whitworth Express Mauser bolt rifle.
I've seen many other serious hammers that were very, very accurate.
In regards to DG hunting though, it's "not so much the arrow, as it is the Indian" who will make the difference when the time comes.

There is a great network of hunters and shooters who visit this site. It's not at all uncommon for these members to get together for big group hunts and just to burn powder together. Many times in the past new enthusiasts have come along for these events and have gotten their first opportunities to handle and shoot real-for-real big bore DG rifles.

--Tinker