Hi OP. Sorry your frustrated with the forum, it happens. Don't think I was involved in any of your previous discussions but it certainly sounds like you have done your homework and know exactly what you can carry and the reasons why. That's a great start.
As to your actual problem: with just under 900# tongue weight available you can safely tow a 6000# trailer. There a butt ton (technical term :)) of light weight framed TTs out there with GVWR under 6k# and all of them have small cargo capacities so you don't need to do the unloaded weight plus cargo exercise just use GVWR. Search the internet for the trailer floor plan you want that is under 6k# GVWR and go see it a dealer. To hell with what the dealer wants, look at what you want
Good Luck