Just a heads up: in case you haven't noticed every other article on the web this week has included a feature on drafting merfolk. Pick orders, top commons, uncommons, etc. Historically this kind of confluence of well meaning advice (from so many sources) is (not too surprisingly) almost always followed by a flood of MTGOers following said advice.

That being the case you may want to use additional caution when drafting the little blue(and white) men this weekend. Unless you are getting strong signals or feel like sharing your merfolk with 2+ other drafters at the table you may want to avoid this kettle of fish all together for a couple of days. Try out that Kithkin/Giant archetype or GOBLINS/elves, anything that doesn't require you to fight over dowsers.

Best of luck