Thanks guys for the references & accolades WRT the project. Like anything looks like theres a range of possibilities to meet varying wants/needs. E.g. some survivalists are into the super quiet thing.
My minimalist (cost-, weight-, difficulty-, efficacy-wise) project is more toward the something is better than nothing end, which was my target. Looks like it cost < $150 or so all-in. Adding a bit more for 2X+ thicker engine insulation might make a nice improvement & maybe lower CFM/quieter fans. Guess the key "innovation" was IDing the bread keepers as endcaps which allow for at least some baffling.
So my gen setup ends much quieter than most other little gensets in the campground & LOTS quieter than the monsters my neighbors use during power outages (OT, don't get me started). Does the job for that too because I made my forced-air furnace pluggable using heavy grounding plug/receptacle so I can round robin the gen between fridge, furnace, etc.
