Hire a certified welder. A professional.
I am a certified welder and a welding inspector.
American welding society.
You cannot weld heavy plate with a 110V wire feed.
You cannot add rake to a stock frame that is only 1/16 thickness.
Most after market chopper frames are 1/8 thick, and 1.125-1.375 diameter/
Some down tubes and backbones are 1.5 - 2 inches
Make sure the design is roadworthy.
A trike may carry 3 people. Think of their safety.
On a Roadstar Adventure.