TGJB -

I am starting with the assumption that (even absent bleeding) horses run a little bit faster with Lasix than without it. My question is how you approach a race in which all the horses have prior form with Lasix but run without it today (e.g., a stakes race) in the middle of a card with Lasix allowed for most horses. If you emphasize a variant based on how fast all the races on the card are run (the constant track speed approach), the stakes horses will get slower figures than if you emphasize how well each horse runs relative to its prior form (the projection method approach).

EDIT: Thinking about it further, I suppose the same question applies in reverse when you have newly turned 3yos running on Lasix for the first time. Do you assume they'll get a Lasix-induced improvement or look just run back to their prior form?