Yeah a little rake should do you just fine. Maybe 1/2" or so ought to do it. I doubt you'd need much, but you could test it.
Measure the rear height next time you plan to hook up the trailer. Once you're hooked up, measure it again. The height/rake should be the same if the bags were able to adjust for that load. If not, whatever the height/rake difference is before and after is how much rake you should maintain so you tow level.
I've heard that argument before (on other forums too), but IMO it seems flawed.
They aren't adjustable "on the fly" to account for a random heavy load. You have to take the suspension apart to adjust them. People will usually reply that despite that issue, you can adjust the parts you have rather than buying new parts which in theory is cheaper. Except Bilstein 5100's tend to go for about $100 each, so $200 for the set if you're doing the front or rear only. You can get a Motofab top hat spacer set for $40 on ebay. Here's a
LINK from the first listing on saw by typing "leveling kit Ram 1500" into the search on ebay.
Even if you decide to replace that with a different height kit, you'll only be spending another $40, so you'll have $80 into both sets. That's not even the cost of one Bilstein strut. So you don't save labor because you have to take the suspension apart to adjust the height, and you don't save money. I would contend that Bilsteins are a great choice if you want a different strut, but they're no more logical than a spacer if you're unsure about what height you want to use.