Thanks to Ice-9 on FSB for tracing and supplying the schematic. The original of this pedal used 2SK208 transistors which are only available in surface mount form. I have opted for J201's in the layout, but a bit of experimentation may be the order of the day in terms of trying other JFETs, and associated components to get them to bias. So this may be one for the tweakers at this stage until we have some good results with the alternative JFETs.
Note that the input to the cab sim, would come from the output of the main board, so you would either have two output sockets (with and without cab sim) or you could have a single output socket and use a toggle to true bypss the cab sim.
From the manufacturer: