I would use Super UDT first and Amsoil second. I used Amsoil 30 hydraulic oil in the front axle because I had it. I did my 50 hour service draining about 49 quarts in total (at least thats how much went back in, figuring cylinders, valves, lines held the rest). It was very easy to just use a standard oil pan for engine oil changes and put the plug back in when it was filled. Dumped that into some empty 5 gallon paint pails and then eventually into the empty hydraulic oil containers that were used to fill the tractor. My advice, get some paper towels (rolls).
I'm about 15 hours from my 100 hour oil change. That is just engine oil but figure I will use a synthetic like Redline oil 15W40. I know they don't show a filter change but I always do, I know it doesn't need it but the idea of leaving a quart of old oil in the filter just never seemed right. Filters are so cheap to buy. I'm sure your hydrostatic filter will need changing. They aren't too cheap but built like something off the space shuttle. Rat...