I have this plane with an OS1.08 in it. It pulls it around nice. Its not a missle but very scale. I own 2 G90s. One is in the GP Shoestring. great engine but if you think that G90 is going to pull that Modeltech, your sorely mistaken.
Mine weighed in at 9 3/4lbs with that engine. Your looking at least 9lbs with your 90. Isn't gonna happen. If cost is an issue go with the Magnum 1.08 or if not, stick a 120 fourstroke inverted in it. other options are the 120 Thunder Tiger, Webra etc. A .90 won't do it. later