I feel that weight training is the most imortant part of my armwrestling workout. Of course table time is important, but I think you should limit it to once a week. The reason is that, if you train hard, will get some injurie because of the fast movements that often occur in table practice.
Training with weight will strenghten your ligaments and tendons and make you stronger in a more controlled way.
There are many ways to improve your armwrestling in the gym and like other sports you sort of need to find what works for you!
Hand strenght and good wrists/forearms are the key to improve your armwrestling.