How low do you let the 450's tank go on the Kaza stretches, and do you strap a can?

Fuel planning is the bit of my Spiti sheet I rewrite most, so I went looking at what the numbers actually say rather than what I assume.

BikeWale's mileage page puts owner-reported economy at about 30 kmpl, which on the 17 litre tank is a comfortable day between pumps on tar. The catch is that none of us ride Spiti on tar the whole way, and a loaded bike crawling in second through a water crossing is not doing 30 of anything.

So two things I want from the club. Where does your fuel warning actually come on, and how many kilometres have you honestly got left after it? And for the Kaza side, do you bother with a jerry can on the pannier rack, or do you treat the stock tank as enough and just top up at every chance you get?

I lean towards topping up obsessively and skipping the can, but I would happily be talked out of that.