I'm one of those students who has the books with the notation and tab underneath, it is almost impossible I think to not look at the tab when it is just there. However, every other bass player my age that I know relies on tab
I personally think that the best thing to do would be to separate the two parts out like was mentioned above, but only if economically viable. Otherwise you would be defeating the object of having the tab in there to start with, to reach this wider market and get more sales. Otherwise the 'traditional' line of tab under each line of notation may be the best option...
Oh and I'd love to 'trial' your book like
Craig
Edit for spelling.