Weight, but the software I use (Brewtarget) also gives the percentage. It comes in handy when you don't want to have a grain besides your base malt above a certain percentage of your total grain bill.
Primary: One Buck Bombers IV
Bottle Conditioning: One Buck Bombers II and One Buck Bombers III
Now Serving: One Buck Bombers I
Drunk: Lil' Sumpin' Sumpin', Celebration Ale, Fat Tire, Two Hearted Ale, Speedway Stout, SNPA, SNPA w/Simcoe, Moose Drool, Dale's Pale Ale
On Deck: BIG 7