Wouldn't that be nice if the wheels were the steering problem -!!!!
I also doubt that is the problem, although it would be a major added leverage for any ruts or uneven ground to take revenge on the steering linkage. with them wide the tires are not just pivoting around a point, but rather rolling around an arc and the distance of the radius of the arc is the increased leverage that the tires have. I know that it does not take that much to make the tires try to turn on their own when the tires are normal.
He did state there is no muffler, but I had planned on running one parallel with the ground with a turndown at the end like a Kubota.
The actual Yanmar muffler can be horizontal. The exhaust flange is a square so the mount can be rotated 90 degrees and bolted back on, like in the first pic below. This is of a 186, but it is possible on the 1510 also. California has a muffler like this on his 186 also.
I have a welder and a grinder so I can do all sorts of damage.
I have made most of my implements that I use. You can check them out in the "build it yourself forum. The links are in my signature.
Also considered making my own ROPS. Advisable?
If I were in the States I would buy a ROPS for my tractor. Then you are sure that you are getting a design that has been tested and is safe. All the dealers will have them. I see for example that
LMTC has it for $629 made for the 1510. That would sure save a lot of cutting and fitting and give a whole bunch more confidence in the final product. You might be able to make it for less, but not that much less and it would take a bunch of time. Use your energies for making things by making some implements to use with your tractor.
Your first pic. [Calif how did you put the thumbnail here in this situation?]
It looks like the loader install got the hyd directly off the pump and uses a QD. I would be afraid I would get in brush or something and the QD would come disconnected and result in one ruined pump. NEVER start or even run the starter with that QD disconnected as serious damage can result from the dead head situation.
I also do not see the Thermal Start cup?

It is the translucent plastic bottle beside the radiator hose in the second pic below. There is a larger bottle which is the overflow for the cooling, but the one I am talking about for the TS is below the radiator hose in the pic.
Third picture
The 4 wheel drive lever is way too far forward and down compared to mine and others when the 4 wheel drive is engaged it is forward, but not to that extent. Compare the relative positions of the lever in
this picture to the one you posted pictures of. The lever with the red knob on the left of the tunnel is the 4 wd lever.
Mike