Trim Tabs

I asked the question in the design forum, but think it is probably better asked here. I also got some additional experience that adds to the question

I have a US Navy 26' personnel boat that is identical to the ones at this url http://www.marinesalvagepi.com/26personnel.html

I'm interested in adding trim-tabs, but don't get a great feeling about the sizing guides given by the manufacturers at their websites. I'd like some independant advice from people who have experience with tabs on their own boats and/or know the calculations behind the design decisions for the tab dimensions.

I'd also like to know how tabs would affect the seaworthiness of my boat at displacement speeds in a follwing sea? I was out in that #@$& in the Santa Barbara Channel yesterday. Although I NEVER plan to be that stupid again, I don't want to handicap myself too much if that sort of situation sneaks up on me. Would the tabs give the waves something to grab onto and abuse me more than the same situation without tabs?