My 03 F-150 was rock solid towing my TT at about 34" tongue to rear bumper with the bike rack pulled out. It's all about the WDH adjustment.
Read this. The front axle weight (or estimate by fender height) needs to return to unhitched weight. The rear will sag a little, maybe 1.5" if the front is adjusted well. Rear suspension design (indepentend/coil springs) has nothing to do with how much weight it can carry. That's just spring rates.
Not all 30' TTs are the same. Mine is 6500-7000 pounds loaded. Some are over 10k pounds loaded. You need to understand how much yours weighs as the receiver, payload, and rear axle weights may be over their ratings with a 30' TT.