I think very few of us have modelled Sangsetia. Examples are few and far between. Mine is still only "bath tested" after 15+ years!
I have two 777motors from the long gone "model motors direct". I think I fitted 40mm brass 3 blade generic raboesch props. 8.4v Ni-Mh batteries for power. As said it's only bath tested and does draw a good few amps (I forget how much, but maybe not rediculous for brushed motors). I keep on re-wiring mine as I had troubles with the original esc's and mixer. I'm waiting for the combined 20a esc and mixer to come back in stock with component shop.
I know tendency these days is for the Colin McRae style of sailing, but from memory she wasn't that fast at full chat.
Sorry I can't be more help. If I didn't have the motors already fitted for so long I'd maybe be looking at 5 pole 540 size motors, or similar to what you found. It's reasonably big, but not a heavy model at all. I ditched my SLA's for it very early on!
Not sure if that helps but keen to see another Sangsetia finished.
Rich