Help with hydraulics

Hi everyone I'm a new member here but I have followed this site for awhile. I see so many great articles from so many very smart people I just had to join. And now for the fun.
I started a small project awhile back It's a wheel loader similar to small bob cat skid steer but with a bucket on front its wheeled but I made tracks for it from chains and 0.250 plate. It sets on four 15" wheels rear powered. frame is made from 2" x 4" x 0.125 Wall rectangular tube. Lift arms are 2" x 4" x 8' x 0.125 wall rectangular tube powered by two 2.500 x 18" Double acting cylinders. Bucket is 4' x 20" x 20" x 3/16" plate powered by one 3" x 14" double acting cylinder centered.All controled by two each two spool valves. So far build is going along fine. When finished it should come in at about 800 - 1500 lbs and is for home use only.I also have used
1.500 x 1.500 angle . 0.125 plate and 2" x 4" x 0.125 wall tube for misc. Bracing and such.
Now for my question the hydraulic wheel motors and pump or pumps if I need more then one( hope not ) what size should they be. Speed not an issue but would prefer some amount of torque for wheel power. Any suggestions or ideas would be welcome an highly appreciated.

Thanks. Jess.

Generally speaking for your drive system you are going to want a closed loop hydrostatic drive 1 for the left And one for the right they do make a tandem pump with a piggy-back auxiliary for the rest of the hydraulics on the machine. You could go with a pair of geroator wheel motors are used on exmark, Toro, Snapper, ETC, Zero turn mowers https://www.amazon.com/dp/B081NXSMGT...xpY2s9dHJ1ZQ==
Combined with a pair of these for pumps
https://www.griggslawnandtractor.net...variable-10cc/
plus you will still need a small gear pump for the lift hydraulics
I don't find the piggyback pump set
I have several of the wheel motors but the ones I have are much larger than what you are looking for and I have a quad pump set but it is 4 fixed displacement pumps connected together.
You also did not mention the engine you are planning on using I would recommend not smaller than a 21 to 24 HP gas or diesel
By using the above mentioned variable piston pumps you will only need some linkage connected to the pumps to make the skid steer go forward or reverse