Don in Phoenix:
There ain't any easy way, ya gotta do the math. Get a pencil out, list every load, in that application I would assume 100% duty cycle. Ask the customer what he plans on ading over the next couple of years, total it up, add 25% and then round up to the next larger size panelboard. Convenience outlets with no load are calculated at 180 vA. Or you can just fake it with a 225 A MLO 42 circuit, NQOD bolt on box, fed with copper enough to overcome the distance, then they will say nice things about you long after you're gone...
[This message has been edited by Almost Fried (edited 10-06-2006).]