Number 1 consideration is to have the beam height at a comfortable height. For most folks this will waist height.
If you glance at my avatar you will see the hitch is where the out-feed tables are. This is because at the time I was splitting into the back of my one ton truck. Next splitter will split to the rear so the splits will go into a trailer.
My current splitter has a 5' wide axle for stability going highway speeds while pulling a trailer behind it. I will be doing the same thing with the new splitter only the axle will be located under the out-feed tables.
If you are going larger than a 16 gpm pump you will need to use 3/4" hoses & ports for everything going to the valve/cylinder. Leaving the valve going back to the reservoir if you want to go bigger you can but don't have to. Make the suction hose going from the reservoir to the pump the same size as the pump's inlet.
Mount the reservoir higher than the pump if possible to help prevent dry starts. If you mount the filter higher than the reservoir & in a location where you can hold a can/drain pan under it, you will minimize lost fluid & mess when changing the filter.
If you plan to split in >= 90°F an oil cooler would be a smart addition. You can find them used from combines with 3/4" ports for around $100. You want to keep the oil temperature < 180°F.
If you look at the wedge systems commercial wood processors use you will see they are narrow & tall. This will allow you to cut through really gnarly & stringy pieces with less effort. My wedge is 21" high with the 4-way installed.
I like a longer log lift where the angle at the bottom around 120°. This makes it easier to load larger rounds & holds more rounds when using it as a staging table.
I split everything I can find. Elm, Hedge, ... with a 4" cylinder, 16 gpm 2 stage pump with the pressure relief set at 2,500 psi using a 4-way wedge 95% of the time. Cycle time is 8.8 sec with a 24" stroke.
