I will say stock refinishing is a personal preference. Eventually you will find what you want/like and stick with it. IMO, original military finishes were created using either what was considered the best available in their time or what was expediently available to get the job done. Substances from boiled linseed oil, ballistol to used engine appears to have been used on German k98 stocks over the years. I am sure the texture ingredients of these finishes probably changed over the years as well. What was good for the stock 55 years ago may not be good for it today.
Must not forget the russian shellac and cosmoline added to the wood. Whichever method of finish you choose, remember that you should Not oil the barrel channel of the k98. I say this because almost all vet bring backs and non-import marked stocks have a dry unstained appearance in the barrel channel and magazine area of the stock. Good luck and enjoy your endeavor.
I am no expert, I can just let you know how my experiences have turned out for me. I have used Howards feed-n-wax almost exclusively on my stocks for the past several years. It does protect the wood. It helps clean it and it only takes one or two coats. I like the way it high lights the woodgrain. I have also used boiled linseed, Formby's traditional "Tung Oil Finish" mixed with mineral spirits and Birchwood casey "Tru-Oil" on mauser stocks. I since removed the linseed oil and Tru-Oil from the mausers and applied the Howards. I do not like to continually sand the wood with either fine sandpaper or 0000 steel wool. I like the sort of rough feel of the military wood.
To clean a milsurp stock I generally use the following procedures:
The wood is wiped down with mineral spirits to get the gunky cosmoline and crud off. I then use denatured alcohol to remove russian shellac and paint if desired. If it is hot enough outside I set the stock out on the back deck for a series of days in the summer and keep it wiped down as cosmoline weeps out. After the stock was weeped out, I used a $25 water steamer to target nooks and crannies and raise dings in the wood as needed.
Be careful to avoid cartouches. After that I used a a Very Worn and soft green pad, warm water and go-jo to clean the stock and towel dry. It amazes me how much dark crude comes off during this part. I let it dry 24/48 hours and the apply Howard's Feed-N-Wax following the instructions on the container.
Howards Feed-n-Wax - provides a nice easy to apply non-caustic finish. Cleans and treats the wood without darkening the grain. Does provide prolong protection of the wood from the environment and is easy to repair.
Forby's Tung Oil - 3 to 1 mix with mineral spirits. I do like the tung oil finish and kept that on my M48A yugo mauser and the M1 Garrand. It took 18 hand rubbed coats to get it to the right feel and look (allot of work and light fine rubbing with 0000 steel wool) The tung oil provides a nice look and provides the long lasting fine protective finish.
http://www.surplusrifle.com/shooting/tungoil/index.asp
Boiled Linseed oil - One or two coats is all that is needed. Darkens the wood to much for my taste. I like to see the wood grain. It can become sticky. It does not provide as much protection from the environment as other products (i.e. tung oil and Howard's feed-n-wax).
Tru-Oil - Birchwood casey contains linseed oil but is more of a hard gloss finish than I like on military wood. I tried it on a couple of my RC's, but removed it because of the results. I have kept on my marlin 30-30 and springfield 22 sporting rifles because it has a high gloss shine that is more appropriate for them.
I assume you have read the above forum stickies on finishes. However, another site has a stock finish forum that may provide more info in you quest for knowledge.
http://parallaxscurioandrelicfirearmsforums.yuku.com/forum/view/id/101
I will post some pics in your other thread shortly.... Gota get some pics first and do some honey doos done...