The base clevis fitting was done when adding the bottom web bolsters to the frame. Now the clevis of the shaft end of the cylinder was carefully fitted to the base of the ram. Two 5/8" bolts pass through the ram faces and core and hold the assembly together in the frame. The hydraulic cylinder mounting was then completed.
After studying several internet sites with technical data about hydraulic fluid filters I confirmed again that a person can easily overdo on information. How important is it to understand the difference between a return line filter (low pressure) and a supply line (high pressure) filter? What about the micron size - 10 or 20? One friend told me he ran the machine he built for 30 years without a filter.
What kind and how much? I bought 10 gallons of Mag 1 R&O ISO 68. I kept and stored the containers the fluid came in in case I need to drain it all out some day and keep it clean.