spark plug gap?

hi there...just bought a 73 ts 100. Do you know the plug gap on the plugs? also, it has been modified when the top end was rebuilt and it has two plugs in the head now. any idea what the head might of came off of? also do you think i gained or lost anything with the compression ratio as a result? do you know if a 1978 exspansion chamber and carb woulb fit a 1973? one last thing, do you know the weight of the oil that goes in the crankcase
thanks!