Yes, it's normal for some models to have slight nose up angle for the horizantal stab.
There's plenty of books or informtion you can google on basic of R/C flight.

Did you put foam under the main wing ? Sometimes the wing won't sit at the proper angle becuase of the foam.

You can also try adjusting both of the airleron (lower both sides slighty) If the airlerons are sitting sligthly too high
in neutural posistion , it'll cause a model to fly nose up.

You also try adding washers behind the engine mount to change the engine angle....I'd try adjusting the airlerons first.

It's also normal for a model to gain altitude if you add more power. Sort of like flying into a headwind. you know...more lift