Thanks for posting this Carin!! Yes this is a great idea for AMHA shows too. We looked into it last year but then decided not to add them. I think we were planning to add just 3 or 4 classes. All the forms you need are on the pinto website (www.pinto.org) and as I recall, in addition to the judge being carded for Pinto (lots of the AMHA judges are) the show manager and show secretary also need to be PtHA members. Well, the names you put down on the forms need to members...
In addition to the payback, which might draw people seeking Pinto points, you also have people going for Pinto Horse of the Year Awards. And yes, you have to EARN your Pinto points, but once you have 3 entries in a class, they add up fast. Each additional horse you beat (after the first 2), earns you one more point, up to a maximum of 6 for a first place with 8 entries. So in a class of 8, first earns 6 points, second gets 5, 3rd gets 4, down to 6th place gets 1 point. More horses past 8 in a class does not earn more points so it makes sense to split classes that have 15 or more horses. New England now splits halter classes (mares vs. stallions/geldings) but they ran them together for years. Some judges will ask the age of the horse while judging and they all ask the gender as you come in.
If you are thinking of adding hunter or jumper classes, you need to know that Pinto has some very specific requirements for their jumps. The standards cannot be higher than the jump itself. See any of the many jumping photos on our website for examples.