send them to the local theatrical dealer to pick up a " Luminsuck" - thats that thing that picks up footcandels where you dont want them and deposits them where you meant them to be :) whats even better is if you get the supply house to play along and ask them if they need a medium or large...
here are a couple thoughts:
i agree, defaulting to the number of potential circuits you have now, is probably not a good first appraoch.
info i usually start with is :
1 how big is stage deck
2 rigging height of lighting pipes
3 distances from FOH positions to stage deck
4 budget...
i suggest a few guidelines for a buyer :
1- budget, be realistic and dont waste time ( yours or a sellers ) be honest, if you have 1 - 5,000 then you can access certain lines of product, 5-10k others and on and on. whatever your real budget is- tell the folks quoting you right up front.
2 -...
strand AMX ocasionally reversed the order of its pin out. try swapping the clock plus and minus lines at the rack. if that fails buy a dove convertor ( yes i think gary still does that ) AMX was proprietary to Strand, and sometimes other mfg. AMX wont work. sorry.