I'm in it for a little longer ;)
He is quoting the 100AH units at $750 CAD, the 300AH units are $2250 (same price per AH. I'm not sure whether it would be better to go with 4 x 100AH to start and add a few more if really needed later. Limiting to 400AH would give me a higher C factor when spiking at 150A (0.4C vs <.3C at 600AH)
The other vendor (Total Battery) has not returned to me on my request for quote so far...
He's put it in writing on the quote that the batteries are returnable for full refund if I'm not satisfied.
I kind of like the idea of supporting this kind of entrepreneur, if the risk isn't outrageous, he seems like an interesting guy based on his other business.