Re: How would one cut the foam insert to match rifle?
There are plenty of threads on the Hide (if you search "cut foam") with tutorials/pics...and no, this is not a way of saying "use the search function"
Hot wire, electric carving knife and a sharp knife are the favoured methods.
All I use are one of those cheap extending snap-off knives, chalk and a ruler.
The tools are just part of it. The end results will be more to do with how you use them and the time you take to think it through.
Take the time to do the lay-out properly to maximise the use of space, leave 1" minimum between objects in the case.
Once the lay-out works for you, trace around the items to be put in the case with chalk - keep it right up to the edges of the item and then cut inside the chalk line for a tight fit.
Make sure the blade you use can fit right through the foam or you'll end up with edges that are as rough as a badger's arse and cut along a straight edge. Use long, smooth cuts - not short hacking motion.
It is really easy and, unless you have a really busy/complex layout - I can't see any reason to take it to someone to do.
The kit costs pennies. Just take your time.