Not sure how to make it more sherry-like, but I think I remember seeing a thread asking about it.
OK, simple solution...BUY MORE GEAR!!!
Oxidation comes from aeration/splashing during racking. By racking too early you can get diacetyl (beer), but not for mead that I am aware of, but we're only talking a few points (like 0.002 from FG)...and I've made a dozen or more meads.
I actually have a couple batches going and about 40 more pounds of honey to use...