Now, of course when you draw the actual full-sized plan, you start with the nut/bridge/string taper... but I don't see a problem with sketching ideas on notebook paper. The important thing is to transfer a sketch into a workable design.
This sounds like a headache. I think there will be a lot of trial and error and a lot of erasing. My suggestion: Draw your bridge line (the theoretical bridge-end of the scale length), draw the nut, draw the string taper and the edges of the fingerboard. Then redraw the body around this. It will come out differently from your sketch, but it MUST come out differently, because a sketch hides dimensions that won't work on a full-size guitar. Keep looking at your plan from above, so that you can see the whole guitar. Your eye will point out things that "don't look right" as far as the shape goes. Keep in mind principles of balance etc.
Lastly... you seem to show a lot of initiative. While you still need to do a lot of reading, I would encourage you to go ahead and build your own neck. It's not that hard and then you have control over the feel of the guitar. You can carve the neck to fit your particular grip or playing style. It's also a great learning experience. You'll make a lot of mistakes but your next neck will be much, much better.
EDIT: I don't know if you're considering a one-piece bridge/tailpiece, but this is a good choice.
http://www.stewmac.com/shop/Bridges,_tailp...und_Bridge.html