In general, oil/varnish finishes aren't really meant to have a high sheen, but instead have that "in the wood" finish and feel. 2 coats are all that is necessary (as per manufacturers' recommendations). Any buildup in the sheen is not the oil, but just more varnish coating. It's much quicker and economical to either buff with wax or switch over to a varnish.
Let it dry for at least 3 days, but closer to a week is probably better. It should just barely smell like linseed oil if at all once it's dry. Next, it depends on the look your after (here I'd highly recommend a test piece for comparison that has the same 2 coats of Danish oil). Like Mike said I'd try:
1) Buff with paste wax which will be a soft finish with a nice luster.
2) Although polycrylic should be fine, I'd tend to stay on the oil side and use a wiping varnish like thinned polyurethane (50/50
gloss polyurethane/ mineral spirits). You could always try a test piece and see how the polycrylic performs as well. Lots of premixed versions of wiping varnish out there as well. See the Howard Acheson's post for application:
http://www.ncwoodworker.net/forums/s...ight=wipe+poly
To repair: Wax can be removed with mineral spirits and then reapplied. A varnish needs to be stripped (chemical or sanding) but is much more protective.
Note that Danish oil is
usually mostly mineral spirits (~50%) with some raw linseed oil and a little varnish. Raw linseed oil takes much longer to cure than boiled linseed oil (3d vs. 1d in optimum conditions). A homebrew recipe for oil/varnish is 1/3,1/3,1/3 boiled linseed oil (BLO): mineral spirits: varnish (polyurethane or other). apply like danish oil except it dries a bit faster. then buff with wax or topcoat with varnish. Alternatively, if you want the oil look and varnish sheen/feel/protection, you can simply coat with blo, let dry, then topcoat with varnish. Oh the possibilities...
HTH,
Sam