DAP INC 18152/11440 10.1oz White Alex Plus Acrylic Latex Caulk with Silicone, 2 Pack

Is this the best product for sealing/waterproofing an exterior sliding glass door jams leading from a bedroom to a patio?

Do you need a caulk gun to use these bottles?

Is this good to close small holes in the walls? Or little gaps between the floors and the moldings?

if i sandwich a 1/2" bead between 26ga sheet metal and flat side of a PT 2x4 and leave in the Florida Sun?