Date Example.xlsx

This is a simplified example of a much larger workbook that I am working on. I need formulas to insert into the yellow highlighted cells to find the start date and end date of each "fund" (each column). Each fund starts with a $0 balance, and increases by $1 every period until it hits a maximum limit (in this case, 5). After each 6 month period, part of the fund rolls over into the next "open" fund that has not yet hit its max limit of 5. I need the start date row to have a function that looks up the date of the first cell in the column that is greater than zero. I also need a formula for the end date to lookup the date in which each fund first hits the limit of 5.

I tried using some different INDEX and MATCH formulas, but none of them worked properly. Help would be greatly appreciated!