I use the oil filters from the Toro dealer and they are $9-10 each. I used the Hydro-Gear filters when I changed the fluid in my ZT-2800 hydros. They were $10-11 each. For the oil, the manufacturer said:
"Typically, an engine oil with a minimum rating
of 9.0 cSt (55 SUS) at 230ー F (110ー C) and an
API classification of SL is recommended. A
20W50 engine oil has been selected for use
by the factory and is recommended for normal
operating procedures."
I went with castrol GTX non -synthetic.
The Hydro-Gear shop manual is available for download from their website.
Just my 2 cents.
Bruce