Shaz I know nothing about the Viper, but I do use crow on my Flash. This is what I do. I have the crow mixed in with my flaps on a mix switch so I can land with or with out crow. I find that in high winds crow turns the Flash in to a kite. So I don’t use it on landings in high winds 20+ MPH. I drop my gear, then flap and crow. Make a lap or two to get the feel of it and the speed right then come in for a normal landing. You will find it will come in a little nose high like your F-15. When you cut the throttle it will sink faster than with out crow so be ready.
You must be standing on a high point at Chatfield. When I fly the elv is about 5400ft. But at 95deg the density alt is about 9500ft...