Hi Scott,
I'm no expert in rubber power, but I don't think the Cougar would be suitable at all. It is a great shame low thrust long duration motors suitable for model jets are not available in the US
.
Dr Jones has developed a Rapier Analogue, but volume production and distribution are a real huurdle.
Have you thought of 'micro' EDF? A 'power train' is available from SAMS Models in the UK. Here's what it looks like:
This gives about 22g of thrust - good enough for a good, if not stellar, performance.
I will send you a copy of the plan.