need some expert opinion. is the pt 630 head shape and size exactly the same, similar, or completely different from the lm radical mp. i grew up with the pt 280 but after several moves have lost and eventually moved on to lm radicals with lots of lead. have a chance to get a pair of 630s cheap, but forgot what the head shapes look like compared to the lm rads. also what are peoples experiences of changing the CAPs on the 630 to regular bumper guards/grommets? just had shoulder surgery. what are the best grommet replacements to use on the 630? the lm radical mp grommest or the i.radical? string tension. i use 68 on the lm radical mp, but notice alot string in the 50s that have 280/630s on this board. do i have to adjust tension for the 630 or stay the same?