I have been lifting my Ferris ZT since new using my FEL. I actually installed a 3/8" lift chain in the OEM holes in front. I just hook the chain hook into the chain on the mower, hook the other end in my FEL hooks and lift to about 45 degree angle. This is plenty to clean the deck and change the blades. The safety police will yell loudly about getting under the mower held up with the FEL, but I think it is much safer than a mower lift where it could fall off the lift. No way is the chain coming off and barring a busted hose (next to impossible odds) it isn't going to fall. If I were worried about a busted hose, I could fabricate a cylinder block to install on the main lift cylinders so they couldn't come down.
As for engine oil etc, I let it set a couple of minutes after lowering it to allow any oil that might be up in the cylinders to settle back. So far with 600 hours, no issues from doing this lifting.