Have read all the replies to your question and find them very interesting.
Based on my experience running a Sig 1/4 size clipped wing Cub for several years and a bunch of ST 2500 and 3000 engines in various planes over more years, here's what I've found.
My Cub flew with an OS 1.08 because that was the largest glow engine that I could get at the time. I did not want a clunky Quadra or any other gasser as I preferred to have everything enclosed inside the cowl. Power was more than adequate. On floats, at instant full throttle from idle, and full up elevator, there was no take off run at all. It was instantly into the air and climbing without hesitation or lack of speed. Most likely I'll build another one day. My preferred engine for that will be an OS FX 1.60. Still want all the engine and exhaust inside the cowl. And I want the plane to be on steroids. The 1.08 was nice. I'd just like more power, ability and excitement.
The ST2000/2500 will fly the plane. But it's much bigger and heavier than the OS with now power advantage.
My large Tigres all ran flawlessly with Fox idle bar plugs. Not an issue or a flame out due to a plug. Some people preferred K&B plugs yet I never had them work reliably. Why? Who knows? My fuel was a maximum 5% nitro. My preference was Byron fuel since it had the right composition and content oil for the Tigre and results were consistent.
The large cats were not difficult to set up. You need to take the time to learn how a Super Tigre works. It's much different than say an OS or Enya engine. As with anything else, once you learn their characteristics, they are very easy to start on the first flip every time - if they don't you've done something wrong - and run reliably with no need to constantly fiddle and adjust. My carb of choice was the OS 7D which gave much better performance though than the stock carb. Fuel consumption was about 1 oz. per minute. To me, with the low or no nitro blends and not excessive consumption, fuel cost was not an issue.
As for gas engines, I run Zenoah, the main reason being that I can get magneto ignition. I despise batteries. They always fail - always at the worst time. They require constant babysitting and still they fail. Doesn't matter what type - NiCad, NiMh, lipo, carbon-zinc, lead acid wet cells, gel cells or whatever they are. So the fewer batteries on which I depend, the better.
As for selling the Tigre, do so before you get too itchy to run it, bench or otherwise, since that will devalue it. The best return comes from new in the box, with the original box and paperwork. Even with just a bench run, it's no longer new in the box and devalued. Forget selling it on this site. Go to the bay. Check what's happening there with current listings and recent sold items. Somewhere about $100 + or - sounds to be about the correct range. Put whatever you get into the replacement engine.
If you don't care about what you'd get selling the Tigre, by all means, run it - first on the bench. It will not come into its own and settle down to what a Super Tigre is until you've got some time on it. You've also got to learn its characteristics. This is easier on the test bench than in the air. Prior to this, you may think that it's a piece of junk and that it will never be worth anything.
Finish the break in by flying it. The ground on a bench is not a good place for that.
Whichever route and whatever engine you ultimately choose, enjoy your Cub.