The first step in designing a plane is deciding what performance you want.

Since you talk about verticals, I assume you want strong acrobatic or even 3D performance.

You're on the right track, thrust would have to be higher than weight by a good amount to hover. However, most sport/pattery style acrobatics can be performed with much less thrust.

Wing loading doesn't matter if you are hovering, but obviously matters the rest of the time. As you noted, a higher wingloading does require you to fly faster to generate enough lift to stay in the air, but there is more to it than that. Lower wingloading will generally improve acrobatics as well.

The reason you see a power system that produces less than 20oz of thrust advertised for a 50+ oz plane is that they are expecting slow/parkflyer type performance, a slow "floater", not an acrobatic plane. So you'd want to get the weight way down for that power system to get acrobatic performance out of it.

My designing has been glow-powered so far, and mostly combat planes, so I don't have more specific help for you in your exact case.

There is a program called something like "motocalc", and a few websites that have calculation programs to predict performance of various motor/battery/gearbox/prop combinations for electrics. You'll want to get familair with using one of those, and it's limitations, there are a lot more variables in electric power systems than in glow.