I realize this is an old thread, but many people will use it as a reference for new systems.
One important point to be aware of on this circuit. If you are running in PID control mode (i.e. the contactor is closed) and turn off the heating element using the using the PID controller (I am guessing it probably has a manual on/off button) then the wire to the element that does not go through the SSR is still live and touching it and anything grounded (possibly your brew kettle, brew stand frame, controller box, etc) will provide a path for current and provide yet another way to test you GFCI...
To prevent this, add a second SSR in series with the other contactor input, and wired to the same controls as the first.
I would put two indicator lights on the heater side of the contactor. One from each output to neutral. With on SSR, the non SSR side would glow continuously while power is applied while the one on the SSR side would go on and off with the heating element.
why not replace the contactor with a manual DP switch? still has the issue above, but "should" be cheaper.