-50% that's a crazy discount. Like said I'd maximize that too even if that meant sacrificing something else.
About Mod3 (which I haven't personally used) the idea sounds great, but I am sure you will not want to take binos off your face once you've put them on so it kind of doesn't give you a loaner no matter if you think it does
I haven't still seen much info on the 51deg optics. Nor on the BNVD body if it's actually good or not.
One thing that's certain is the 51deg eyepieces have shorter eye relief compared to the standard 40deg. How much will they distort if used beyond the max eye relief is something that I'd be interested because it may not be the most comfortable experience having your eyelashes against the glass. Or almost.
Not sure if I remember this right, but I think they have an odd cutoff for power like maybe it was an hour and then it shuts off automatically. If I remember it right, there could be something in there that notices you are moving and don't do that auto-off via a timer. I'd be annoyed if my binos were to shut down unexpectedly.
The BNVD with filmless tubes would be something I'd go for assuming the body & optics are good. Their standard 40deg optics are good at least. Then like mentioned get a Gen2+ for a loaner later on.