Splicing Instructions for Samson rope is located here:
You should follow the instructions for the particular type of line you are splicing because cover (and sometimes core construction) varies between manufacturers. The reason that the Samson lines (and others) require a core-core splice is because the cover is tightly stitched and you can't bury both the cover and the core into the neck of the eye (it's too thick to pass the cover through). Since the strength of these lines is mostly in the core a core-core splice will retain 90% of the strength of the line.
In terms of difficulty; it's about the same in terms of time/effort to do a core-core VS a standard eye splice. Both type of splices are tedious and if you can't do it from memory (lots of steps) you have to read the instructions as you go. The difficulty in the core-core splice is getting the core splice to milk back into the cover; and whipping the excess cover tightly to the eye. Cutting dyneema/vectran to taper the strands is not easy either. You have to saw on it (won't cut even with the sharpest scissors); it is tough stuff!! It's easy to cut it as a solid line but cutting the individual strands is a chore. I don't think 25 bucks to have someone make eyes is unreasonable; but it's a good skill to know how to DIY also.
Stripping the cover WILL reduce the useful life of the line to a large extent. For halyards you can reduce the wear by replacing the cover at the eye so that there is a 1-2' length where the line has a cover (to prevent chafe on the masthead sheave and cut-through of the line on the shackle). If you strip the cover you should also run messengers so that the exposed section is stowed in the mast and out of the sun which (will deteriorate the exposed core). The wear/tear on halyards with stripped cover is just another "boat buck" expense for serious racers. I won't strip the covers on our halyards because we are not competetive racers. You can strip the covers on spinaker sheets so that you reduce weight of the lines pulling down on the sail in light wind (helps the sail 'fly' better).