We’er looking at using a conveyer belt to load our shooter. But we were wondering what would be best, using 1 or 2 belts?
please describe how you would be using the two belts
We are thinking of having the motors running the conveyer belt on both the top and bottom of a (magazine) channel leading to the shooter. The channel would be at a slight (15/20 degree) angle
With a single belt and a fixed surface the balls can rotate against each other and bind up, so you need to control how closely they’re spaced apart.
With two belts there is no such problem, but the mechanism is heavier.
is it hard to get the belts sinked? or does it not matter?
We used a single conveyer belt pickup in 2009 with a board on one side to apply pressure as not to fall. The lunacy balls were covered in cloth(which slipped when rubbed together) as apposed to this year’s balls which are extremely grippy when rubbed together. With a single conveyer belt the balls need to roll up the other side so when two balls come in contact it’ll get in the way of the system working. This year we’re probably gonna go with a double conveyer belt system ourselves but I’m sure you’d be able to make a single belt system work somehow too. Good luck! 
Do you mean “synchonized”?
Not terribly important if they’re traveling about the same speed. I assume you’re going to use a high-traction, flat belt though.
they work better when they are close in speed. it really doesn’t matter if they’re perfectly in sync.