Not knowing what one is doing is common here. I often have retrain myself on things I "misfile" between projects.
However, a lot of people here spend so much time finishing wood that I would give up in disgust or slash my wrists. Most of this extra work comes from using modern mass produced finishes which for the most part are made for indoor use and are 70% mineral spirits with almost no solids to fill anything with. Spar varnish, the good stuff and some tung oils are OK but thinner than was used by gunsmiths back in the day and generally full of stuff like Stoddard Solvent. Many modern finishes are too hard and brittle. From reliable reports Permalyn falls into this category. As do many of the old finishes used on furniture and musical instruments. On Maple unless its very poorly prepared (like the Bettis rifle mentioned above, once its had a soaking coat of lighter oil and turpentine a very nice finish can be done is one or maybe 2 coats with a thicker oil. But like many things one must have patience since it will not fully develop for a few days or even longer in some cases. Linseed also tends to dull somewhat when its not handled. But even a years old finish that looks a little flat will brighten right up just by handling or rubbing with the hand. If some resin is not used, I cheat as previously stated on other posts and use Grumbacher's Oil Painting Medium III added to finish to add some resin. Its easier then buying the resin and cooking it in. When it still had all the ingredients listed the only thing it had that was not "period" was some lemon solvent IIRC. The new bottle don't show whats in it.
The problem with stock finish in the modern would is that by about 1900 the technology was lost. All paint and varnish was now factory made and by the 1940s-50s people who did stock work were jumping though all sorts of flaming hoops to finish walnut. All because they did not understand old school stock finishes and were using stuff like "bar top varnish" which was harder than heck apparently, and other factory made stuff made for INDOOR USE.
The linseed oil available was just paint thinner and not properly prepared for stock work. Though it will do a paint on let it soak, wipe it off finish in a day for a hunting gun. Who needs a glittery SMR, for example, anyway?
True if you let the Linseed oil "varnish" (back in the day anything that would dry to a shine was varnish) set too long its gonna resist removal. And it gets all ugly and wrinkly in a couple of hours in the sun. The initial sealer coat will generally come up out of the pores with the warmth but since this is not glass hard (or close it sometimes seems) they will come off. Or one can go out and wipe it down with a hand or soft cloth when they appear. Since I do not want the finish too hard to remove easily I do not put a coat on to set overnight for this reason. I do all the application and removal during the day. Unless its winter when there is no outdoor sun to use. Then things get somewhat slower.
There are people here that simply detest Linseed Oil for a finish. But I have seen original guns with Linseed varnishes that, unless worn away still had ALL the their varnish over 100 years later and the finish was not broken ever at rounded dents unless severe. This applies to Hawken rifles like the Bridger Rifle, in Helena to guns of the post Civil War era such as Ballards and other BL or late ML. If the finish is REALLY looked at it may amaze some to see that the brush patterns or skin ridges of the applier are still visible. The stuff was pretty thick and did not "flatten" well.
But people for the most part do not take the time to experiment and they believe labels which generally apply to painting interior trim or a chest of drawers.
Are there store bought options? Sure. I used to top coat wet sanded stocks with Linspeed. I DO NOT recommend wet sanding its a toxic process with any modern varnish. One can take Tru-Oil once described to me as a cheap phenolic varnish and mix it about 50-50 with off the shelf linseed oil and it will work well. Its got good color and will be harder than off the shelf products. This product is one a DO use for very minor touchups on stocks in a "crisis" but its so few and far between that I usually have to buy a new bottle to do it. I have heard good reports about Chambers Oil finish and there are some others from specialty wood working/finishing companies that do not look too bad and have smaller percentages of solvent or none at all.
Dan
