D15 Auxiliary Hydraulic Valve

I’m wanting to add auxiliary hydraulic valves to my D15 so I can run a two way cylinder. If I’m doing the work I would like to pipe it so a second spool would control the lift arms. If I pipe the second spool valve back to the original aux. valve (like the one in the picture) would this control the lift arms up and down? I realize I still would have no draft control but I’m hoping to get better/smoother height control of the lift arms. I realize I would have to pipe the current supply line to an open center control valve, run a return line back to the sump and have to put the original control lever on the console in the up position. Would this work achieve what I’m wanting it to do?

You cannot connect two individual aux valves like christmas tree lights, one after the other. You probably will explode the first valve when you pressurize the second valve to max press. Get a 2-spool valve and you can do exactly what you want without issue.

Ideally, you should try and find valves that have a "float" position in them, especially for the lift arms. That type of valve will cost more but will operate soooo much better.

Doing my research for this and a question that comes to mind is do I need to be concerned with overheating the hydraulic oil? If I leave the hydraulic lever in the up position the pump is constantly pumping/flowing oil to the new aux. valve and back to the sump, will the hydraulic oil overheat being there is only 2.5 gallons in the sump? Or should I be putting the console lever in the neutral position when not using the added aux. valve (which then seems counter intuitive)? Or am I missing something?