You've put a lot of work into your post and it's to your credit that you think about poker this much.

Risk and uncertainty is so inherently subjective that you may render any half-life calculations redundant. Also, what if you set a target of 'withdraw $2k in 6 months' and your chosen site goes splat in 5.5 months? I'd rather leave X on a poker site, X being a value between:

- The minimum I need to play (say, 10 BIs. Not your whole roll)
- The most I'd be willing to risk losing if said poker site went all slide whistle on me.

So you have a floor and ceiling amount where you deposit or withdraw as it is reached.

Finally, variance. The only one of your target BB/100 winrates that is over 100k hands in the 4 month period is the first one (1k hands per day). Sample size isn't big enough to iron out natural variance and deviation.