I don't think I have a photo of mine, but the thing is simplicity itself: a short length of 1x4 with a V notch cut in the upper end. To support it in the gudgeons, you'll need to get a set of pintles. You need the ones attached to flat strips as opposed to a U shaped bracket, but they should be readily available. They are called "transom pintles" because the flat strip version would be mounted on transom. (The U bracket versions are more common, those normally go on the rudder. You might be able to adapt the support to accept those, if you are clever about it, but then you would lose the simplicity of using a single board of 1x4).
In either case, measure the pin diameter on your existing ones, to get the matching size.
You mount the pintles to your mast support and then hang it like a rudder. Done.
Amazingly, even a single board of 1x4 is strong enough to support the rear end of the mast. I have described elsewhere how I
secure the mast for transport.