I converted a similar Accel SBC dual point but, it has the vacuum advance. Works great.
I shaped a thin piece of aluminum like the stock distributor housing (that gets clamped down) and used the Accel housing screws to hold it on the bottom of the Accel distributor. I am able to use the stock hold down.
Can't find the pics. I think I posted it on this forum though.
https://www.fordbarn.com/forum/showthread.php?t=243704
Post #8 shows my pics.