Making the span shorter helps - but not because it increases wing loading.
I am surprised that so few "inquiring minds " never check thrust to weight - before they even try to resolve performance.
a simple 10 lb draw scale will check thrust for almost any engine up to a 91.
For basic workable performance --a 7 lb plane should have 9 lbs of static thrust -
also it helps to have short span and low wingloading.
As for aft cg - it helps but really makes a problem in some designs.
Here is the magic formula:
as much power as you can get PLUS as light as you can get it - none of the rest is all that important.