I have some experience in finishing (built furniture as a hobby years ago) before the audio bug bit me.
If you are going to use a "varnish" as the finish, I strongly recommend using a "sanding sealer" as your initial coat. Laquer is NOT COMPATIBLE with a varnish finish.
The sanding sealer is very easy to work with. After it dries, lightly sand with a 220 grit sandpaper (very fine). The beauty of the sanding sealer is the ease with which is sandable. In addition, it will turn into a milky white dust as you sand, giving visable indication of when to STOP SANDING. This helps prevent sanding through the finish into the initial stain coat, a real no no if you don"t want the final project to look splotchy.
After the 1st and following varnish coats, use a "block sander" (a rubber block that the sandpaper attaches to .. available at local hardware or home center for about $7) to smooth and give bite to the next coat of varnish. Use 220 grit sandpaper for these coats also. The total # of coats is up to you but I would recommend at least 4 coats of varnish. The more coats the "deeper" the final finish will appear (I used to use and liked the look of 7 to 10 coats).
The final step will be to hand rub using "pumice stone" and then follow with "rotten stone." IMPORTANT - DO NOT DO THIS STEP OF POLISHING UNTIL THE VARNISH HAS HAD TIME ENOUGH TO FULLY "CURE"...AT LEAST 30 DAYS! Failure to do so will yield a CLOUDY FINISH which you will not want at all!!! Use a "felt" block for these stages and use oil for a lubricant along with the pumace & rotten stone powders.
The last two steps are quite labor intensive but will guarentee a very professional looking finish. Working with the flat surfaces of the speaker will make this entire project easier. The longer you rub with the "rotten stone" the glossier and deeper the finish will appear. You can add wax, but it will not be necessary or be of any advantage with this type of finish.
A good source for various finish techniques will be found in issues of "Americian Woodworker." I recall an article 4 - 6 years ago that discussed in detail the advantages / disadvantages of different finish techniques and various product applications in both appearance and longevity.
By the way I used "tung oil" to finish an older set of speakers about 2 years ago. With out a doubt a much easier application, but not the type of look I had hoped for. The amout of coats you put on will determine how glossy the end finish will appear, but will not give you anywhere near the "depth" to the finish, that the varnish will.
