Stashalong - the new rules

So I'm signing up again for Stashalong, in a bid to get my stash down to a manageable size.
I'm going for option 2 - the chequebook system.

First, I have to work out the full extent of the stash. I've started cataloguing this but it's not complete. Total so far is 41,500 g. I'm using weight as a measure, because it roughly equates to volume, and volume is what I need to lose to make the stash fit into its allotted space.

Ideally I'd like to eliminate 10kg of stash, which is a rather frightening 100-200 skeins depending on the type of yarn. However, I'll stick with this as a stretch goal, with interim targets of 2kg at a time.
Given that I'm not too sure of my starting point, I will focus on calculating usage /disposals and purchases/ gifts ie. what comes in and out. I think that not buying too much will be the hardest thing.

Any way I can get rid of yarn counts. ie. using it, giving it away or selling it. Likewise, if I receive yarn gifts that counts as additions to stash.
UFOs - credit is given for usage of yarn when object is completed.

Short term targets for January
Complete the Finn wool sweater
Make booga bag and Jawbreaker cardigan - both also count for 'It's not a Gift 2'
Rifle through the stash and come up with potential pattern and yarn pairings
Only start new projects from stash yarn