On my GSj-1 how many times should I sand and raise the grain?
I will be using a water based stain so I don't want to have to sand that if it raises again.
I'd do a wipe before staining, then a light sand - you don't need much to remove the loose fibres. You'll probably need to do another small wipe after staining as that will raise some more grain. But very light strokes and fine paper, as you don't want to rub away any stained wood.
I've found that getting the wood wet will always raise a few more strands of loose grain, no matter how many times you do it, so just minimise the amount of times you put water on the bare wood.