03-05-2021, 12:10 AM
It may be overkill but I like to slip a thin piece of wire in the pockets to lessen the sag between tacks. I start one end of the car and work towards the other lifting each pocket till the seam is just below the timber, not pressing, and with a slight sideways tension. I like to stop tacking at a uniform say 4" from the sides. The final underneath finish should then have no tacking pull marks except the extremities and they be in a line.