I have done a few rods and had guidance from people who knew the game, here's what I was taught..............
Remove all line guides and wraps = careful work with razor and peel off the old silks.
If the ferrules are loose, remove them, watch out for 'pinned ferrules' some aren't just glued on.
Remove the old varnish using a good stripper. Work quickly and plan on it taking multiple treatments before you have bare wood.
Examine the sections to see that all the glued splines are solid.
How to Impregnate your own rod
Use a length of PVC pipe long enough to fit the sections, 1.5 or 2" diameter will be good.
Cap one end so it will hold fluid.
Wrap the rod sections with wire or strings so you can suspend them in the tube vertically.
Fill the tube with Linseed Oil and hang the sections in the oil for at least 8 hours.
Remove from the oil bath and wipe the sections with a non shedding cloth and hang them vertically in a warm dry room for 2 weeks to cure.
After 2 weeks hand buff the oil finish and then re-dress your ferrules and guides with the silks you have chosen for the rod. Finish all windings with Spar marine varnish and you're done.
I have done this with the cork grips on and with the grips removed. If you leave the grip on, don't soak the cork. Suspend the butt section with the winding check about a quarter inch above the Linseed oil. The oil will wick up the shaft under the check.
I still have one of the rods and the finish is beautiful, never will need redone again.