RE: HOVERING RATIO???
David, that's the best way to do it. If you're comfortable with your plane's power, you have enough. If not, get another engine....or plane FOR your engine. Best way to get a general idea of what engine to get for a plane that you're ABOUT to buy? Ask someone here on RCU! Different people have different ideas as to what is enough (or too much) power.
Broke n bummin: It's hard for me to believe that your ASP 1.08 has almost enough power to get a 1.5:1 thrust/weight ratio on a 50cc plane!! Most planes that big are about 16lbs. 16*1.5=24. You claim 23? WOW!!s
As for ratios or formulas:
thrust>=weight, good hovering
airspeed=altitude=0, empty wallet unless you've landed.