I remember that plane when you got it those years ago. I think you should go with the 3 engines. It fills/breaks up that big open saucer area. It makes it look more muscular. The Boeing 727 has 3 engines wrapping the tail end of the fuselage, so it would make sense on your experimental craft. It's safer in flight with 3.
I absolutely love the design, it must have been a part of an airport display at sometime. Did the eBay seller say where they acquired it from? As for three engines, not unrealistic at all, the McDonnell DC-10 and the Falcon 900EX biz-jet both had three power plants.
Interesting model.. for my 2 cents worth I think 2 engines is more than enough. Will you scribe some panel lines to add some interest to that big saucer wing?
i like the original configuration because it was very thunderbirds type which were usually impossible designs lol. 3rd engine only needed levelling and the uprights are fins. and ailerons are the flaps ...who ever built this had a very sci fi animation type mind i wonder what else they built..