Yes, the HC2812-0850 and the TP 1320 Lipo is a perfect power combination for the Tantrum. Try a GWS 11-7 direct drive prop for the same pulling power with less amp draw. I've used the 1020 kv model also with good results. Never had a 2816 so wouldn't want to guess at its suitability.
Built straight and light the Tantrum is a superb example of what fine design and kitting can do; kudos to Doug Binder.