I am no expert and have not tested anything myself, but have always been told (and it seems to hold true) that shield skill is the most important then weapon skill. Armor skill is a factor in regards to hinderance as that plays a smaller role as well as burden.

What I have seen that supports this is.. I do better with one type of lance than the other (skill in pike is significantly better than halberd), a ranger was able to better block a lance without hindering plate - that is the opponent would score only a shield hit without his armor, but when he wore it, they were all body or head shots (not recommended because if you don't catch the lance with the shield, you leap off your horse and lose the match), I have done better in a close match without a pack rather than with, and another thing I noticed once was a Paladin with a bond to his horse struck a quintain (found in some jousting practice fields) a lot better than I did, which would suggest that it plays a role as well.

If that rambles or is hard to understand, I apologize.

Sebestyen