From the last post in
http://forum.arcadecontrols.com/index.php?topic=97561.0 you can download "slikstik.iso" which is a image of the CD that probalby came with that cabinet. In its "SlikStik Utilities" folder is a "manual.pdf" from 15FEB2004.
http://www.retroblast.com/reviews/slikstikclassic.html has a link to
http://www.retroblast.com/files/SlikStikUserGuide.pdf which is a 29OCT2004 version of the manual.
A 2006 version of the manual is available here:
https://www.kutek.net/mame_roms_pinball/mame32_config_files/slikstik_controller_manual.pdfbut it doesn't have as much info and its text isn't searchable.
Hopefully one or more of those manuals can help.
Generic PS2 to USB adapters may not work (correctly) with the IPAC4 inside your control pannel.
I have the SlikStik Classic Controller which is the 2 player version, but you should have the same connections. You should have three connections to make:
1. IPAC: USB (with an Ultimarc cable) or PS2 keyboard port
2. Trackball: USB PS2 mouse port
3. Spinner: USB port
I wouldn't use a USB hub, one more thing to break/cause problems.
Note if you're using Windows 10, you must have your IPAC connected via USB (with the correct cable from Ultimarc) to program it. If you're not going to program it, then you can use its PS2 connection.
One last thing to note, you don't need to install any drivers or software (WinIPAC) to use your control panel. You only need WinIPAC if you want to change its programming.