Couple of comments:
1. You're only as strong as your weakest link. For the Armada, it's the 910 lb max tongue weight. That's the number you need to scrutinize for any RV you're considering.
2. You may not have a choice with the % tongue weight for a given TT. Some are just very nose heavy and it isn't always easy to lower that number. For example, my TT has a 15% tongue weight unloaded and all the storage is up front. I can't do much to decrease my %.
3. Keep in mind that the main issue is towing stability. You'll probably have enough engine and brakes, so you can go and stop. The issue is keeping everything under control once you're under way.
Having said all that, I think a 5K lb dry TT sounds pretty safe (assuming you'll be at less than 6K lbs loaded up). Beyond that, you have to ask yourself about how far & often you'll tow, and the conditions where you'll be towing, e.g., flat vs incline, a lot of cross winds. If you plan on any cross country trips, you *really* want as much extra towing capacity as possible because you're guaranteed to run into some challenging conditions at some point.