Thanks Matt for your great advice!
Actually it's the second bagged plane build of mine, still need to learn a lots of skills from you guys.
I've noticed Oleg's build guide as Thomas send to me, the reason why I did't hollow-out the foam under the skin edge is that I used carbon cloth on both side of the wing, (I can use fiberglass strips for the bottom side, but I just don't like what it will looks like as you need to sand the carbon surface.) I just want to save the weight, but I did't know how the enforcement works.
And the join of the spars, oh,man! I just missed that important part!!
I have make some big mistake when I build my Neos. one is I drilled the hole of the spring in a wrong way. it should be reverse. two inside the front, and one hole near the horn....
I may change the tails to a lighter set, I'm looking forward to test Thomas' new CNC tails. lol
Thanks again for your comments!