Bob,
I don't have a two stroke .90 in mine but it will probably be plenty of power.
Mine with YS 1.10 finished out under 8 lbs. I did use carbon fiber wheel pants
and landing gear but it is plenty light without these changes. I too used the
Radio South hinges and they worked perfectly. I almost changed the strange
pull-pull set up but I am glad I didn't because the stock arrangement works
just fine. Good luck with yours , I am sure you're going to like it.

tommy s