It may surprise many people but the higher elements were only optional extras to non-US agents until very recently when they became standard. I ran 3 coffee kiosks with 2 group 2kw steam and we survived quite high traffic at peak times with no fuss. Swapping the steam for the 2kw element is a good idea for home use and you would never know the difference.
I do like the idea and practice of PID on steam boilers in a commercial environment as it is one less mechanical part to go wrong. But really for home/office I personally wouldn't bother.
To do the wiring it is quite simple. The A1 and A2 wires on your contactor go to the input of the SSR. One set of the contacts L1, L2 or L3 go to the load side of the SSR. The other set of contacts get connected together.
This is basically the set-up

I put the SSR in a cold place under the machine. I would advise against mounting the SSR where the existing contactor is as it get's rather warm. I suppose you could if you bumped up the SSR to a higher amp rating.
I can post better info if anyone wants.