In my last post I forgot to ask, did the used SME table come with an arm board and if so, which arm was it drilled for? The arm you choose must be compatible with the arm board. If it didn’t come with an arm board (which is unlikely) you will have to buy a new one either used or from SME. If you have to buy a new one they will have to drill it for the arm you choose. If you buy one used, then that will determine which arm you will need to buy. Hope that helps.
Scot