I happened to have this double rod cylinder lying around and used it. A double rod cylinder is not necessary for your saw. Use a standard single rod cylinder if you like. This cylinder should have piping between the two ports, and one path should have a check valve and nothing else. This will always allow the saw to be raised with little resistance. The other path should have a adjusting valve like the one on my cylinder that also shuts off to hold the saw up.
Of course you will want to ask me where the second path is on my cylinder. I never bothered with the check valve, and while lifting the saw, I open the adjusting valve which allows the fluid to transfer over to the other end of the cylinder. I have used larger bandsaws (not real high end saws) that included a hydraulic cylinder and feel mine works equally well. As far as the amount of fluid that I am using, I filled the cylinder full, removing all the air from the cylinder. I then forced out enough fluid through a loose fitting for proper operation and called it done. I have not had to re-visit the amount of fluid since completing this conversion several years ago. I have been using automatic transmission fluid in the cylinder on my saw, for the past several years with good results.
I removed the cylinder to show you how I mounted the cylinder. It is a 10 second job to remove the cylinder, as there is only a nut at the one end holding the cylinder in place.