They are pinned with 2 (1/8) SS pins I never liked soldering bolsters. Did it once and never again.Beautiful work! Is the bolster pinned & soldered?
About 11/4 x 11/4 x 11/2 This will give you a piece of steel 1 1/2 x .150 x 1.25*1.25*1.5/1.5/.150 =10.4 inches long.Seaweed pattern. How big of a block did you start with?