Breadboard max current/voltage
It varies from stripboard to stripboard.

One location I found (which seemed to cite Vero, a major manufacturer of stripboard, though I couldn't follow the citation) says "For 1oz Vero with a trace width of 0.19mm the quote is for 3.5A @ 10C and 6A @ 30C" - the post seems to indicate that 1 oz is very common.

He does warn about the holes; the traces are smaller at the holes.

I have seen other sites which suggest soldering a wire along the track, to increase the current that can flow.

This is not original research, and I have no specific knowledge to confirm this. 
http://www.chatzones.co.uk/discus/messages/1218/2470.html?1141515383