I'm on a 6box skunk streak (for silver). Thankfully I was able to score on a bag earlier this week. If you have liquid cash buy as many boxes as you can!
I really think Boxes depend a lot on unknown factors.
1. Will the people at the coin processing place realize they are servicing a coin hunter and go out of their way to skunk you? As somebody posted awhile back this can happen...
2. What is the size of your area? If it is a big metro area, there is a lot more halves coming into to coin processing place which could be a good thing.
3. How many other CRH are hitting halves in large amounts? If a ton of people are searching halves the dumps will severely outweigh all the fresh coins one could assume.
Honestly though 4 skunks in a row, as much as that sucks It could be a lot worse, and I personally wouldn't even get alarmed until I skunk 10-12 in a row. Try different banks too. I'm on a 6 box skunk streak with one bank in my area and hit silver in about every box from the same bank company just a few miles away. There is no rhyme or reason to it. I would keep hitting those boxes until you can't stand it anymore.
Think 8 would be about my limit, not due to cash flow but rather the max I would want to get rid of a week. Might change once I start finding silver though. Banks seem to be more inclined to accept dumps of dimes as opposed to half dollars though.