So maybe this will help some of you out there. With the 4 to 1 buy ratio, and the rules of diminishing pool, I found that to buy equipment during downtime took some math. Some players may not have realized it, but it does become hard and expensive to properly pick up gear. I mean, if you think about it, a character with a 3 dice pool can't even buy 1 hit... thus actually can't buy anything with an availability rating between adventures. So I broke down the ratings as such and looked at the minimum dice pool needed to buy stuff
CODE
Availability    Pool    Interval Breakdown
1    4    1
2    5    1+1
3    6    1+1+1
4    7    1+1+1+1
6    8    2+1+1+1+1
8    9    2+2+1+1+1+1
10    10    2+2+2+1+1+1+1
12    11    2+2+2+2+1+1+1+1
15    12    3+2+2+2+2+1+1+1+1
18    13    3+3+2+2+2+2+1+1+1+1
21    14    3+3+3+2+2+2+2+1+1+1+1
24    15    3+3+3+3+2+2+2+2+1+1+1+1
28    16    4+3+3+3+3+2+2+2+2+1+1+1+1
32    17    4+4+3+3+3+3+2+2+2+2+1+1+1+1


I broke down the interval successes, beacuse it can help in determining how much you want to pay for an item % wise, in case you need it faster.