Seam sealer fail - help

Thanks for all the tips. So I settled on 3M 08307, 2 tubes, and 1 gun. So as I wait for delivery, I am concerned how to tool this stuff, if possible. Dry time? Like as it gets down to below the windshield area, it needs to swoop up and then under hood. Not sure how a self leveling product is going to go up? So can I spread it with finger?