Constructing my own Fat Bike Cruiser

[jameschance]

Hi
I am looking to make a fat bike similar to the Moke or Super 73.

The bike is only for a bit of fun i.e. going to the shops/pub/beach. Does anyone out there have any experience of these bikes and do you have any tips?

I am experienced in TIG welding tubes for frames, but I'll be honest I've never made a bike before. I know it would be easier to buy a bike, but that's no fun. The motor would be the Bafang G06 hub (because I have been given one) and the wheels 20" x 4". Other than that nothing else has been tied down.

Can anyone answer any of the below questions:
What size tubing and material are these type of bikes made from?
Bottom bracket width?
Front hub width?
Does anyone have any drawings with frame geometry?

Thanks in advance.