A little Sucrets tin turned out to be a good size for my QRP dummy load.
A short section of 1×4 sliced in half to about 1 cm thick serves as the base. The dummy load is screwed onto the board and the board glued into the tin. For extra security, I put three screws through the sides of the tin into the board.
On the antenna analyzer, it reads pretty close to 51Ω and 1.0 SWR between 3-10 MHz. Above that the impedance creeps up to as high as 55 Ω and 1.5 SWR below 28 MHz. SWR shoots up pretty high in the VHF range.
I don’t have an external connection for the power measurement yet. Still need to figure out how I’m going to do that. For now it will be an “open the lid” measurement.