Process Explorer : Which version of Debugging Tools needed?

I apologize in advance if I've missed the answer to this question, but I have looked around; if it's out there it's just eluding me. 

Here's my question:

Let's say I'm setting up Process Explorer on a particular machine, and I'm trying to configure symbols.  What determines which version of the Debugging Tools for Windows I install on that machine?  For example, if I'm running Process Explorer on, say, a Windows XP box, do I use the version from the Windows 7 SDK? or from an older SDK / Debugging Tools package? Or do I take the Windows 8 SDK, install it on a box with a supported OS, and just copy the resulting dbghelp.dll from there to the WinXP box?

Any help with this will be much appreciated.  And again, sorry if I've totally missed this one. (I really did look! )

Thanks in advance!