The cub is not a trainer..and that .25 sig CUB kit is not a beginer's kit.
It's just a box of sticks. It's not difficult, but the odds of you building it correctly as a first kit is slim.
I had the same idea you have. I never got a chance to fly it becuase i nevered finished it.
I wanted to make it too detail and scale..plus the way that kit is designed...one hard landing...you're done.
Or it would be difficult to bend those wire gears back into place...like a regular trainer.
It's not a flat bottom air foil, plus the placment of the main wheel will cause it spin more during ground handling.

If you build a regular trainer the fuse are going to be lite ply and jig...
You bascailly use rubber bands and the fuselage will lock in into place & straight
The Eagle II, LT40 , Tower. You can frame and cover it in weekend or less...bascailly get to an ARF stage.
Then another weekend to install the engine and radio EQ.

Get a LT40 or whaterver arf, trainers and just convert into a tail dragger.
You can mount the mains slightly forward of the LE so it won't spin on the ground as much
It's a trainer...a learning tool. You'll make mistakes. Get a trainer that will handle your learning curve.
Don't worry about it looking prudy...all you're going to see in the air is something that looks like a T.lol
Put contras color sceheme on the bottom of the wing..so you'll see the model better.

If I was your instructor...I'd make you master the proceedure truns and do touch and go at will...before i give you your wings.lol
Not just fly the modle and cross your fingers for a landing.