I'm not sure if this should make a difference or not, but I was able to get Visor to work by changing the order in which I performed the actions:
1. Uninstalling TF
2. Reinstalling and updating TF
3. Disabling SIP
4. Enabling Visor
5. Re-enabling SIP
The only difference for me was that in prior attempts I had enabled SIP and installed the helper, and then immediately rebooted and re-enabled SIP. This time I disabled SIP and then enabled Visor prior to rebooting to re-enable SIP.
This may have nothing to do with the fact that Visor is now working for me, but I thought I'd send it along just in case.