The MAC43 I used in that video is a 4.5W coil, and the WAS 2.9 board driving it has nothing more than a FET linking battery to coil. It was designed to drive humphrey noids, so I had to increase the power handling of the board to increase the maximum ROF and avoid brownout. Similar things happen with Spyder boards.
In most cases you can get away without, or the OEM has built in superior power handling schemes already, match the the solenoid they're using.