You have to look at the entire package, and often past glow experience won't help all that much - they are usually so vastly overpowered, it doesn't matter as much what prop is used.
Basically - fast models will use a direct driven smaller prop, a slower model will prefer a larger, slower revving prop. My two 300W models are opposite ends of that spectrum - one burns the sky up behind a 8.5 x 7 on direct, the other acts like a slow Sumo-parkflier on a 12 x 10 geared 3.7:1. Both use the same battery packs, BTW. The fast one is an Aveox Embat - sleek, thin winged and hand toss launches real easy for a 54oz model. The other is my design, with a fat, stubby wing, UC, open cockpit fuselage and much bulkier all round.
Low thrust at low speed is embarrassing if the model only flies at a very high speed. The FAI class pylon racers are a fine example - they take the first lap of a race to get going enough to unstall their little, high pitch props and start really hauling. Not a fun model to fly for fun, I'd reckon, and an Olympic level javelin thrower may be essential for launching to stand a chance.
If you have wheels on a model, you can stand slower initial acceleration - the ground doesn't mind holding the model up a little longer (unless the runway is short
). If you can't hand toss a model to a speed it can reasonably fly at, misery and rebuilds await you.
Props are interesting devices. My beloved CAP 232 is a converted glow model. As intended, it would normally fly with around a 10 or 11" prop on a two cycle, maybe a 12" on a fourbanger. My usual 14 x 10" (geared MaxCim brushless) barely rates a second glance in an e-power setting, but wet power fliers are amazed at that much prop on the model. I once flew it - very well, too - on a 12 x 11 at an electric site and was ribbed for flying with a tiny little prop! With a 14 x 10, the initial take off roll is slow, but things soon get fun and the wings take over real fat. Good job - hand launching 6.5lb would be overly taxing.
Best tip - rely more on examples seen in reality than in *calc programs!