Derek - the Fortek - was that one of the "usual" 20-30A SSRs?, many of the cheap trial-based SSRs require a 30+ VAC switching voltage. But, you should have been able to get the LED on the unit to light/extinguish on demand. That I'd be looking at in the first instance to confirm.

For the relay, with the BOB - use the onboard relay configured through J5/J6 to provide direct 12V switching to the relay that you have. My thoughts are that the onboard Opto may not switch enough current for the relay you have - using the onboard relay to drive your relay should be reliable.