I'll echo some of the other responses. Your idea would work but id lean more towards a dedicated scanner. Buy the best 640 12-micron scanner you can afford as you'll be looking through this 95% of the time and your scope maybe 5%. Unless something has changed recently, I'd also stay away from the pulsar axion scanners, they perform poorly in humidity and there are a lot better options out there for that price range. The number of thermal optics that have hit the market in the last couple years is crazy and that's why in my earlier edited post i recommend calling Jason @ outdoor legacy. These guys get their hands on everything and if you talk to them & give them your budgets and desires, they will get you set-up perfectly.