So XSplit 2.1 has introduced some changes to the way it handles SWF files. It no longer loads SWFs through swfwrapper.swf to enable volume controls. What this means for you is that files are loaded relative to where your SWFs are stored as opposed to where your XSplit directory is. This is a pretty nice change. As this basically makes the process for usage roughly the same between both XSplit and OBS.
When the new version of Streamcontrol is released (hopefully soon/early new year) my recommended way to use the older overlays and probably newer overlays would be to copy the Streamcontrol exe to the same directory as the SWFs and run it from there. This helps isolate your settings for each set of overlays rather than dumping everything into the XSplit directory. And is something I’ve already been doing for my own stuff for some time now by using the little documented .nowrapper function in XSplit. And in the future this should make setup a lot less fiddly.
In the meantime, you can largely follow the same instructions for OBS to set up the overlays for XSplit. Make sure you change “XSplit directory” under settings to the same directory you store your SWFs in and you should be good.