http://data.energizer.com/PDFs/l91.pdf
Might be worth looking at this charts, the blue lithium compared with the grey alkaline.
I use two lithium's in a Fuji which has 3Watts battery drain according to the spec, and an older Olympus camera that takes four cells. The Fuji camera has to be set to alkaline and not rechargeable. But we are drifting off the original subject of button cells and cheap PP3's. For HT purposes ordinary zinc/chloride PP3's would be good enough.
http://www.kitronik.co.uk/index.php/...de-battery-9v/