I've found the valves, and had one quote for the direct sequencing valves. And unless I find a much cheaper source, Electrical may still be considered. The quote I had, one sequencing valve was more expensive than a double acting solenoid operated spool valve.
I was looking at the circuit diagram last night, and have decided that a double acting spool would be a better approach, as it simplifies the return lines from the cylinders, and would only require 2 inline check valves to bypass the sequence valves. I'll have to get a good copy of the circuit drawn up and posted on my website. Regarding the rams jamming, the 2 rams never cross paths, which means there shouldn't be any metal to metal contact (unless something breaks). Should the main ram jam, it won't be able to complete it's cycle, so it won't be able to operate the spool valve. This effectively means that maximum pressure will be reached and the machine will stop. Should the feed ram jam, I'll design the feed mechanism so that it has a weak link, to minimize damage. Although the machine will keep cycling with the feed ram jammed, there shouldn't be any major damage. And also, there will always be someone near the machine, either loading in logs, or bagging.
My neighbour seen someone using a mole. They had to lay a pipe up a banking, so they dug a hole at the bottom of the banking, and tried sending the mole uphill. Let's just say, they had to do even more digging to get the mole back
Moray