A T-Top will add about 150 Lbs., depending on how much material was used in fabricating it.
Had this one custom made for my 23', and 2 of us put on the boat with no problem.
It will affect your drift if you do drift fishing, or when there is a breeze blowing as it will catch wind.
It isn't going to hurt you to much as giving you, or making you top heavy.
This one was built for me to what i am installing as to antenna mounts, spreader lights, anchor light, radar dome, and I purchased the outriggers which my man welded in as to the instructions from LEE.
It also is about 2" taller as I am 6'tall and this way I don't bang my head on it.
The better, or should I say prettier rocket launchers where installed becuase Vinney the Welder takes pride in his work.
A good T-Top is going to cost you around $2000.
Just remember you get what you pay for.
If you have any questions, PM me and will be happy to answer for you.