That fan absolutely crossed my mind as I was pondering all the mods. In the end, I decided against it for a few simple reasons.
1. I'm using the oem fan location as an auxiliary, so top efficiency is less important.
2. In stopped or slow traffic, it makes more sense to draw outside air in, and that's when I'll be using that fan.
3. Cost of adding another part
4. Internet evidence suggested a small chance of catching debris between the fan blade and my (now very custom) radiator made me most hesitant. No room left to add a debris shield.
Thankfully, the choice worked out. It was in the mid to high 80s and pushing 90f during the spring ride & very humid too. I had zero overheating issues. I did see some higher temps, but nothing I hadn't seen with the stock VFR.