I mounted both a Mocal brick-shaped rectanghular header tank, and an identical connected overflow "burp" tank, on my scuttle in front of the heater. I fashioned some right-angle brackets and 45-degree support brackets out of aluminium angle, had them welded to hold their angles, and mounted all to the scuttle with nut-serts and hex-headed button bolts.
I have a photo of the general layout, and could sketch how I mounted the tanks on the brackets. I have not been successful in posting photos to BlatChat, so could you send me you e-mail by pm?
Unfortunately I'm flying from Anchorage, Alaska tonight for Christmas holidays in Boston on the East Coast, so I may not be able to respond until I return on Dec. 30, but I'd love to share my "home-made" solution (which does look rather smart, IMHO).
Alaskossie