727 transmission fluid question

I use # 303 hydraulic fluid in the 727 that is in my bracket car. Gives very solid shifts.
I had the tranny torn down recently after 2 years at the track and it didn't need any new friction materials. Only problem is the fluid is clear so it's kind of hard to see on the dipstick. Some folks mix a quart of regular fluid in with it just for the color.
Oh yeah, I think I paid something like $35 for a 5 gallon bucket of the stuff.