No, they don't set a "normal per horse" rate. That's why Rusty won't work. All horses rates have to fall in the same parameters. It's a pretty average parameter tho. At rest Rusty fell at the very high end of it, so that when he was working he went over, and since he had problems cooling, it took him longer then 10 minutes to come down to the proscribed parameters. Now that I think he is well, he "may" be OK. I've never gotten him in good enough shape since then to try.
Anyway, I'd just take Bays at rest, then work him good, let him stand 10 minutes and see where he is at.
Ecurbh could ride with you even if you rode drag, he'd just be at the very back of the competitiors. I've know competitors that rode with the drag riders.
And then there is one other thing. This might not be very ethical but....you could go ahead and ride him as is. In 5 years I've never been drug tested. It's so random, you'd probably get by. If you got caught, just say you didn't know:). I feel bad saying this, but IMO, the drug does not really give him an advantage beings as he has a problem. IMO it kind of balances out.
Becky
Stuff to consider! I don't really think it ~should~ be banned, because it's not a pain killer. It's an aid to circulation that helps him only because better circulation helps his feet feel better somehow. I'd understand if it was an anti-inflammatory or pain killer that would mask an lameness like Bute.
So... we'll see. Hopefully Celia still has the list.