For frags, I would still check with the reefer his tank kH and acclimatize slowly if the delta is too great between my tank and his/her.
For colony, remember to check the base for eggs, scrub them off, coral rx dip wont get rid of pest eggs. I had a tough time battling monti eating nudibranch when the eggs hatches. Lost couple of my fav encrusting montis.
For placement I go by sps species. Strong light species will go up and accompanied by higher flow.