If you're willing to consider using a water borne after the oil and shellac, Target Coatings EM8000cv is a very nice and durable product. Water borne finishes by their nature are acrylics, but it's the end result that counts. They are much safer to spray than any solvent based products, too. (I'm also not a fan of anything "poly" myself...that table base is the first thing I've put any kind of polyurethane on in many years outside of a floor and that was only because the oil based product was one step to get the effect I wanted)
--
The most expensive tool is the one you buy "cheaply" and often...