Don't guess where your CG is, KNOW where it is. Use a
CG sling, period. Shoot, the example pictured is an F-22. How convenient.
I didn't invent the thing, I don't make money on the thing. They are FREE with the exception that you have to have string strong enough to support the plane and that can be anything from kite string to old shoestrings to right off the rack 1/8 inch no tangle chord (that actually would be best). Plumb bobs don't have to be fancy either. A length of kite string with a loop tied in one end, then pass that loop through and around a 1/4x20 nut and Viola you've got yourself a plumb bob.
Hang the thing level, hang the plumb bob from the same point and it will point, EXACTLY where your center of gravity currently is. Then move your pack around or add weight to get it to where it's supposed to be. You should never ever have to wonder if the cg is right if you are flying a proven design that lists where the cg is. You should never EVER trust your fingers and you should definitely never pay more then 20 cents for a full functioning, accurate method to check your cg.
That being said, shoot, I wanted good videos. If the 7 inch prop wasn't enough thrust your plane should have just mushed forward and landed level. Low thrust from a 7 inch prop should equal low power on the 8.
That CG thing just really bites newbies and us old timers too when we get complacent. I watched a hobby shop owner, when I was 17, take a brand new Nosen P-51 up for it's maiden flight. I watched that sucker just snap into a flat spin on his first pass, go inverted flat spin and just total itself. Where was the CG? I forgot to check. The next guy, doing a mirror build, bobbled on takeoff. He got his down with a broken prop. Identical bird. Where was his CG? 3 inches back from where it was supposed to be. I'm surprised it didn't go into a spin taking it out of the van. It'll get us all so don't feel bad, but I HATE IT.
Cuzz it's bitten me before too.
Check it out buddy. You didn't list a bunch of damage so I'm hoping for the best.