I think we are both on the same page.
I understand this is your project, but constructive criticism can be very helpful and beneficial.
You design is good, but the top piece over the receiver seems to be for looks, rather than function, almost an unnecessary feature. I can see problems with case ejection due to the nature of the SKS. Modifications to the receiver ejection port with be need to be done if you wish to retain it.
All you need is this for the top of the receiver.
I think some will agree with me.
But if your hell-bent on the idea, go for it.
If at first you don't succeed, call it version 1.0 and move on!