It's your build, so whatever you decide will come out great I'm sure. Since it's a gas burner my vote is a single tank under the tank body with an access door. This tank style seemed to be common among gas burners.
International R-190 1955 5 by Brian Smith, on Flickr
International R 1 by Brian Smith, on Flickr
You can see the battery tray on the drivers side behind the step on both.