Good Morning jclover41 – I had my teardrop mounted on a 4×6 trailer so maybe this will help. Maybe not.
I just drilled custom mounting holes on the trailer and attached the teardrop with carriage bolts. I had put a 1/2″ sheet of marine grade plywood down (painted with rubberized paint) to gain an extra height (in addition to the risers that CLC included).
My teardrop overhung the wheel fenders. I had to lower them. This caused an issue where they banged into the bottom of the teardrop (mind you I was on rough logging roads)!! Be cautious here….
I don’t suggest removing the fenders. Crap will bang into the bottom of the trailer. To gain extra height (and allow for lowering the fenders) have you considered flipping the axle to a spring over axle configuration as opposed to spring under (if applicable)? Some folks use hockey pucks (I will be doing this in the future).
Lengthening the tongue is a good idea – I had issues with backing up with a shorter tongue. Just watch your tongue weight for handling at speed.
Best of luck – happy to answer more questions.
Joe