I've read the books and online articles and anything else I could find. The consensus is: for shellac, use a pad or a high-quality brush. Foam brushes are strongly rejected.
Cut to the chase: I tried a 4" FOAM ROLLER, and it's working perfectly. I got off-the-shelf rollers from the Borg: white, much denser and finer-grained than the typical gray-black foam brushes, and labeled for "ultra-smooth paint surfaces" (Shur-Line brand). I tested them in pure solvent (denatured alcohol, same source); no degradation of the foam what-so-ever, even after sitting overnight after saturation.
I've been padding a 2 lb cut on a large area (~22 sq ft), but the application and between-coat sanding times became excessive (I like joinery and construction, I HATE finishing). I admit my padding technique is probably less then perfect; I've been ending up with small ridges and imperfections, causing increased time for between-coat sandings (see previous post).
The method is not for the faint-of-heart, die-hard shellac aficionados. When first rolled out, there are A LOT of tiny bubbles (per expectations from Google search). But the bubbles dissipated before the finish set up (except for one spot about 8" X 10", on the 2 lb cut application; 60 deg F;
40 % rel hum), and produced the flattest, smoothest coat of any method I've tried. The method seems to produce a very slight orange-peel texture over the surface, but it sands out with minimal effort. And you have to be careful about slopping over onto the vertical edges. The bottom line: I'm able to coat 22 sq ft in 10 minutes (per Jewitt's spec's: coat w/ the grain, work the wet edge, re-coat, etc.), and the between coat sanding time is reduced BY 3/4. I'll acknowledge that for the final coats, I may go to a quality brush. But I may go back to the roller.The only reason I even considered trying this method (aside from the fact I hate sanding and finishing) is that the shellac I've been using had similar application "feel" (i.e. "wet edge" considerations, set-up time, viscosity, etc.) to epoxy resin I'd used previously on the wherry I'm building. The Gougian Bothers recommended foam rollers for that use; it worked perfectly.
Anyway, all you shellac proponents out there, I'll bet a (one, [1]) beer that you'll marvel at this method, if for nothing else than wash-coat and early finish coats.