Do NOT let just anybody work on it. There are some finicky things about the Reese dual cam WDHs that you need to know. There is a long thread here that is a very good read:
Reese DC installation issues JBarca is the resident expert on Reese WDHs snd perhaps you might try sending him a message.
One thing to be aware of on the cam arm brackets is that the bracket that bolts to the frame has a radius that does not match the typical frame and to get it right, you need to space the bracket out from the frame. If you don't and are just using the Reese bolts, they can loosen up on you and cause problems. Through bolting is one method of attaching the bracket to the frame, but there are some other options.
I doubt welding would void the warranty as long as the dealer did it or had an outside shop do it for them. We just had some welding done on our new TT for some shock brackets without any problems, but the dealer sent it to a nearby frame shop. You might also try contacting the manufacturer for approval to weld.
If you happen to have high tongue weight, that can cause problems. If you are using 800 lb trunnion bars, they are shorter than the 1200 lb ones which can cause problems. Best to read the above thread for things to watch out for.
Posting a photo or two might help.
Once these are set up properly and dialed in, they are great.