Thank you both so much!
rScotty, also, thanks for the great explanation on power beyond and for the links to the lessons on hydraulics.....I'll going through that info over the next few days. Based on what you said, am I correct that if I want to add a tilt cylinder also, along with the top cylinder, I just need to use a 2-spool control valve instead of the single spool valve that Dick called out? And if I had a TNT setup with the 2 cylinders, I'd just need to run my 2 output and 2 return pressure lines from the control valve to a manifold with QA fittings, into which I'd plug the hoses comping off the cylinders, correct?
With regards to the diameter of the return hose running from the new control valve down to the tee on the hydraulic block.....I think it was mentioned that the return hose is typically larger than the output hose. Can that return hose be of too large a diameter, or if I use a 0.50" diameter hose, will that ensure that it is not undersized?
Yes, you can simply use a 2 spool control valve - or as many spools as you want. All else is the same. Any additional plumbing is already done for you within the multiple spool valve body.
Yes to the lines to a manifold with QA fittings. Sometimes the QA fittings are mounted on the control valve itself if there is room, or on short stubby bent pipes that screw in to sprout from the top of the spool valve. In that case, the spool valve body becomes the manifold as well. Small flow means you can use small size hose and small fittings.
The return hose can't be too large. Use whatever size looks and fits right. Typically return is OK if one or two sizes larger than the pressure hose. One size larger for short straight runs; two sizes for longer or complex bends.
Yes, a good way to have hoses built without surprises is to take the old ones to the hose maker.
Eventually you will end up with a box of different threaded cut off fittings used to check for thread type. Hopefully labeled....
The system will bleed itself. Often you won't even notice it happening. Compressed air is a pretty good fluid to start motion. By the time you notice the drawbacks of having air in the system it will be gone. One of the advantages of an open hydraulic system is the vented air space in the return tank/reservoir. That's where the air went.
However, QA fittings do have a check valve inside the end of the fitting. You can see the ball if you look inside the fitting. Sometimes there is pressure on that check valve. Pressure can be from the weight of a bucket drifting down, or can even be from sunlight heating the hose. Anyway, that pressure is enough to make the fitting hard to put together. There are simple hand tools that will depress that check valve and let the pressure off. It usually isn't much oil, but can be messy. Out in the field I bet everyone here has had occasion to use a soft brass/alum. punch and a hammer - or even a stick - to do the same thing.
It sounds like you have it figured out now.
rScotty