ive (sort of) done both. and i agree, i have a garage of vintage bikes so shutting the petock off, for me, is part of the shut down procedure. that being said, i just added an inline valve. which i was told would be too restrictive. bs. i have it on both my C10s.
I also added overflows, easy to do. Have actually done that 3 times, for both my bikes and a 3rd set on my buddys.
Of course, i was told by another group i did that wrong as well. 4 years on: zero issues.
overflow tubes: use 4mm brass tube (hobby stores sell them). I think i used a 3.75mm drill bit. drill out bottom of bowl from top in rigid drill press. chamfer hole slightly for lead in, i used green sleeving loctite. MY tubes are about 4-6mm over bowl line, some prefer 8 or 10mm. taller would be safer for sure, but ive had no issues.
i used a 90 degree 1/4" inline cutoff, you can see it here:
you have to aim the fuel line off the carbs down, run the line across, to the 90, then up to the petcock. the 1/4" valve works just fine. Have done thousands of miles with it and i don't ride them easy.
i made a small plate that screws to the airbox lid existing hardware, and pokes out in front of the LH side cover. thats where the valve is located:
you can get the valve anywhere, but this is fine.
https://www.tractorsupply.com/tsc/product/raider-shut-off-valve-1-4-inor similar.
fwiw, i do still have the stock petcocks on both bikes. both are rebuilt.