1010 after-market hydraulic system

I have already waded through that issue with a 420 (late model 58) and a #35 loader. I hope I am not out in left field but I suspect that your hyd system operation is still basically the same as my 420. Probably a system where the pump is mounted on the motor and it provides a continuous flow of oil to the lift unit. When the unit is not lifting the oil circulates through bypass valve/valves in the unit. If so, you find a place to tap into the Pressure line. Basically you want to divert the flow to go through the control valve/valves for the loader and then back into the pressure line entrance to the lift system. Use an aftermarket spool (open center)with its own pressure relief valve since the pressure relief for the lift is in the lift assembly which is down stream of the loader valve. My 420 has an inline connection just aft of the dash where it can be taken apart at this point for the oil diversion to the loader. Check your system out and let me know if you have the same set up. If so I can send you a picture from the #35 loader book that shows the plumming set up for that loader when mounting on a tractor without remote hydraulics. The old books will show an extra line (overflow /return) from the relief valve to the lift unit which is not needed with modern valves since they bypass internally and use the working line going to the lift unit for return.