I for one, can appreciate the "inventor's" intentional vagueness as I am currently working on products (not SKS related) also.
I would be interested but here's where I think the "inventor" needs to take this. The inventor needs to offer a package so that it comes with this device and two or three modified magazines, and then maybe offer a guarantee on the operation of his package. I find it a big turn off that I have to buy something, modify my rifle, and THEN modify the magazines too! Now if I don't do the modification correctly, I've wasted a magazine. However, if I have a brand new one that I can copy once I'm happy with the function of the package, I could then decide if I wanted to buy more magazines to modify.
Having said all that, I will now say that I would probably be willing to pay ~$80 for "the device" and a couple modified mags.
If that sounds too cheap to your inventor, then so be it, but I own a 'D' and know how hard/easy it would be to make such a thing.