SPS Coral growth and trimming question

[newreefer_59]

Have had this coral in my tank for about a year now, and has really taken off in growth. My question is what is the proper care if i want to trim the coral and/or frag some off to sell, or whatever.

Is is mainly a question of aesthetics or should it be 'cut back' a certain way, etc? Not the best pic here, but this Montipora Capricornis (monti) and a Seriatopora hystrix (Bird's nest). Also, not pictured are 3 resident crabs with very hairy legs and eyes spread far apart. They seem to live on both of these corals........is there a 'trick' to catching the little fellers. I have been advised they may not be a good thing over the long term.

Thanks