Ok, here's a tiny problem:
The Robbjack arbor has a diameter of 12mm, and with a 20mm saw, I guess they prescribe a max cutting depth of 3.5 (since there's 4mm of play).
Fixittt, fix it!
I see 2 options:
1-Go with a two pass cut
2-only do one pass
Either way, the arbor can't be more than 10mm, and should be 9.5mm. Would that even work?
We could go to a 25mm disc, but the arbor hole is 8mm, and the (Robbjack) arbor itself has a diameter of 16mm (or at least the screw does, I think), leaving us with a max depth-of-cut of 4 mm.
With a 32mm diameter disc (max DOC 7.5mm), I'm afraid it would just chop up the block completely, but I'll check.