I like the simplicity of your thinking and perhaps not a bad way...

I like the simplicity of your thinking and perhaps not a bad way of setting up the floor price. 2 call outs
1. EV/EBITDA multiple of less than 10 is considered very healthy, and you are only considering half of it.

2. You have chosen not to appropriate any value to cash with the view that it will be invested into SDV; so by your own logic value of SDV shall rise with time.
Alternatively if you are only looking short term, you need to reflect the cash value.

Offcourse you have also chosen to discount any future growth both in earnings and vertical integration opportunities..