As it turns out, I ordered (from Amazon) several 10mm x 10mm x 10mm heatsinks (which looks like the same size that Seeed Studio sells on their webstore), also purchased some 1x40-Pin Breakaway Strip Headers Male 2.54mm Single Row Straight Pin Connector, 21mm height. The 21mm high headers worked perfectly with the 10mm heatsink height and plugged into the breadboard nicely. The extra height also allows for about a 1mm-2mm gap between the top of the breadboard and the top of the heatsink.
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