This was really helpful. If you let the normal rides calculate their stats, and then test run a never ending custom ride (using zero clearance), all stat calculations will cease - allowing you to freeze manually set ratings.
I was able to get people to pay $20 for a ride with 200 excitement rating. Interestingly, a Carousel ride with like 50 or 100 excitement rating maxed at $1.20 per ticket.
Thanks OP!