The length of time really depends on the time available to work the Epoxy into the seams. I am assuming that you are filling all the interior seams at one time after you have trued the hull. Get things square and true: wind, unwind and adjust the lines then go to filling. If you have warm temps, that really defines how much epoxy and thickener to make. Ice helps increase the working time. Try a slow catalyst if you have it. I mixed enough to fill one seam at a time in disposable cups. Once the catalyst kicks the working time is gone and the fillit become more work. If in doubt work in small batches and work up. I like the monolithic application of the glass strip into the fillit and then covering/wetting out the hull and applying glass to the interior for a monolithic assembly. Maybe others have thoughts on the monolith build up application??? Brian