Thanks to all for the info!

I glued it on with 0 incidence and moved the c.g a bit backwards.The wing is symmetrical and does have a slight negative incidence.I tried it today and it feels like a different airplane much more maneuverable than before.There was a very strong cross-wind so it was actually a lot of fun because the plane would literally just hang in the sky even with the throttle at idle.

By the way, the Stick is V-Stick 60 made by V-mar.They are really cheap and low quality but good enough to have fun with.
The reason why my old horizontal stab broke off was because it just popped off when I was cleaning it.I used better epoxy this time because it seems the fuel made the epoxy go soft therefore weakening its strength.