I think I'm just going to set minimum requirements for either a 31a or 31d and periodically reach out asking if they have one that meets the spec. If I'm going to spend $10-15k, might as well hold out for a really good unit. I need to go get a new eye exam anyway, so if I'm too far off 20/20, I'll just wear prescription under the NVG if I go with the 31a. Or I'll buy the proper diopter and screw it in.
I'm thinking something along the lines of:
Res: 64-72 (will take higher only if the SNR minimum is met)
SNR: 35 min
EBI: 1.0 max
Halo: 0.8 max
Spots: none
I can be a little flexible on EBI and some small spots if the rest of the specs are exceptional. Based on what I've seen so far, these specs might be a bit harder to find in the 31d, but the 31a won't be much trouble finding these.
Let me know if I should add a spec, or if one of the above looks unrealistic. I've only ever used what .gov gave/gives me, so basically a selection off specs is new for me.
Also, I'm trying to stay away from PVS 14 glass. I like the proprietary 31a or 31d better. At least in the samples I've been able to look through briefly. Hence why only 31a and 31d are being considered. Though the Eotech BinoNv-W pretty much looks like a 31d (pretty sure same company making the housing) and has manual gain. So that would be acceptable as well.