I am assuming what he describes as "outlet" is coming from the loader power beyond and his "Power Beyond" is supplying the 3-point. I recommended hooking up the splitter in the power beyond loop between the loader and 3-point, taking some precautions because the splitter valve is not really made for power beyond.
He could connect the splitter between the loader and the tank return but the 3-point will not function. This will be inconvenient since the splitter is on the 3-point.
I agree, and to keep the valve from possible damage, once the log splitter is setup, he could disconnect the PB QD and plug in the log splitter and run the log splitter OUT to tank..
Switching back to 3pt would only take a few minutes.
A two way hyd valve would also work to switched between log splitter and 3pt. .