Take the EAA Sheet metal course, it is offered all over the country.
You will be able to ask the instructors question during the class and after.
One of their good instructors is Ed McGowen and if you Private message me I will send you his phone number. He can let you know the dates of the classes also.
a big help is start with a large table 3 foot by at least 8 foot. Level and well constructed. Or go to Home depot and build their work bench. it will work also but you'll need a couple of them
Smilin' Jack & Anita Hunt
N507H RV7, KJZP Jasper, GA
Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
Hunt Aviation, LLC.
Pilot Service, IPC's Biennials.