You might look into a new, or used Half Pint. I spent one year on cinder blocks , then two years with a Half Pint, and the last ten on a Leader 2x6.
We made some great syrup on the Half Pint and sold it for nearly what I paid for it.
With a growing family; it sounds like your time is worth more than the $900 or so you'll save building up an oil tank arch.
John Allin
14x18 Hemlock Timber Frame Sugar House 2009
Leader 2x6 w/Patriot Raised Flue Pan 2009
Leader Steam Hood 2014 - Clear Filter Press 2015
Leader Revolution Pan and SS Pre-Heater 2016
CDL Hobby RO & Air Tech L25 Hi Vac Pump 2019
06' Gator HPX to collect wood & sap
14' Ski-Doo Tundra for winter work in the woods
Great Family 3 grown kids+spouses and 7 grand kids who like the woods
7th Gen Born in Canada - Raised in Chardon Ohio - Maple Capital of the World..<grin>.