There have been successful combinations of smaller gassers in this size model, MVVS 1.60 for example. Dick Hanson did a ZDZ 40 in a 78" Hangar 9 Edge and brought it out at 13 lbs, but that was with a complete rebuild of the nose and considerable lightening elsewhere. Photos of that project are at http://www.somedudeshobbyshop.com/ under the dhmodels button. Rysium has a nice thread here on RCU for his Powerline Edge project, which was a successful squeaker of gasser into small model.

For a first gas project, I would urge a plane/engine combination that is a known winner, rather than something that tries to squeeze a big object into a small envelope. I have the WM CAP on this winter's schedule, which will be OS 1.60FX powered -- a well-proven combination, which I would recommend with confidence.

If you want a gasser project, I'd suggest a big stick for your first venture (Ultra-stick or something like that), where the set-up is uncomplicated and the wing loading is no more than 30 oz/sq ft. You can have a lot of fun, less frustration and a pleasurable learning experience with such a project. After that, you can experiment more profitably with some perspective to guide your efforts.