This link contains a fair bit of comparative glass, and flourite, information. Of particular interest is that Flourite no longer enjoys the advantage that it had several years ago. A good FPL-53 element in combination with other enhanced glass formulations can surpass a good Flourite setup.
http://telescope-optics.net/semiapo_...o_examples.htm
If you study line entries 15-21 you can see that FPL-53 combinations produce equivalent or better Strehl numbers than CaF2 (Flourite) combos.
If you have time, it is worth reading through this thread on glass on Cloudy Nights, and Eddgie's examples.
It is very hard to beat a modern FPL-53 Triplet APO.
https://www.cloudynights.com/topic/5...luorite-vs-ed/