When I was show barn help, I was paid a day wage. Hourly pay can work out well as long as you are both okay with about 6 hours of paid work on a long winter day vs upwards of 12-15 on a long summer day. You have to also think about I you're going to have this person on as a W-4 or a 1099. Now that I've moved up the food chain a little, so to speak, I'm on salary and sometimes I very much prefer it (paid weekends off once in a while!). And sometimes it's a pain being the one in charge and wholly responsible.
I'd rather not post my salary or previous wage on here right now, but if you like to PM me we can get in touch and I can at least tell you about my experience.