Couple of things about burnishing, the dark grain in the wood is already harder than the light colored. The initial burnish will make the dark grain "stand proud". That's the reason for the fine scraping, to knock off the "proud" humps. This final scraping kind of goes diagonal to the grain, just enough scraping to get her all flattened out again. Then reburnish with just enough presure to flatten the grain again.
The harder the wood, the better this takes. Oak, maple, mahogany, being harder woods burnish faster.
Soft woods like pine, spruce, ceder will take more Scrape/burnish steps to get the grain to lay smoothly at the finish.
Finish stain can be added anytime before the final finish (depending on desired end results).
I usually apply 2 steps from finished (and possibly again on the last step). The grain is usually pretty well sealed by this point. When you stain, stain heavily and wrap with seran wrap (as much contact as possible) and let sit for a day (or more, again depending on the wood). This keeps it from drying out and allows it to set into the wood deeper.
After removing the plastic wrap, wipe it down (with the grain only) with a course cloth like burlap. At this point you'll have a dull shine. Burnishing with some light finishing oil will really start the "glow". Oil sparingly as you go. Just enough to lube your tool and set into the wood. No puddles, or wet spots. Shouldbe almost dry after you finish burnishing the area.
Personally, I like bigger surface areas as a burnish tool (that's why the tea and table spoons). The smaller the tool is I usually find the more liable I am to make the finish ,,, Kind of ripply,,, humpy(?) Larger surfaces tend to stradle the hard/soft grain better.
Not much presure is required (again depending on hardness of the wood you're working). Instead of trying to burnish with one pass, use several passes starting at a point and working progressively away from it. Best to bring the whole thing down in stages (go over it several times). This will give a more even result much easier than trying to go heavy and match it as you go.
Very time consuming, but it doesn't need to be done all at one time. If you go lighter, and do the whole stock, later you can go a bit heavier , then again, and again until you've gotten the results wanted.
The slower you go (smidgen of oil each time) the better it'll be.
I would suggest you do some "trials" before you work on something of great value/pride. There is a technique that you can only learn from doing.
The above is my way, works for me. But I do know others that go a bit differently.
When finished it should look like glass. No pores.
On bow limbs I'd use hot bees wax while scraping/burnishing to seal. Wood bows are very sensative to humidity. Too humid and the bow would take a "set" and loose some cast or become unbalanced at the limbs (loose tillering).
