TT weight is really only of concern from a dead stop and on long grades (as to fuel consumption). The aero qualities are more important in all ways (handling winds, natural and man-made).
Be sure to take the time to dial in the WD hitch on a scale. That will give best feel (and one has numbers for a baseline of comparison for any changes) and best braking. Same for TV tire pressure (as TT tire pressure is always sidewall maximum).
Braking and steering are what really matter. Best tires and shocks are to that end and worth the time in research. Upgrades to the TT suspension (assuming leaf spring type) are second.
Changing trailers is starting at the wrong end of things (if it is otherwise suitable). A better trailer is worthwhile (Airstream-type) as there is no comparison in towing performance to the standard square white box. Plenty of good used ones. In other words, cover the range of what is available, not just weight or length considerations.
Get what you have into best shape. And then use numbers to "see" what you have and experience behind the wheel before more drastic steps.
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