not sure about your Kubota but I have used the rubber ones on my older tractors, I have some that have been in over 15 yrs and never have had an issue/leak with them and they are easy to install!!!! You may not want to go that route since yours is so new but just thought I would throw it out there for anyone that has a need as an option.
They come in various different sizes and due to them being rubber they expand nicely you don't have to be exact with them.