Easy question for me as I rode motorcycles for years.
Dual pull teeter-totter brake lever for both rim brakes on the right, and just the clutch on the left.
Depending on the circumstance you sure don't want to be trying to brake and clutch with the same hand, and you are not using the throttle if you are braking.
The self adjust dual brake lever works like this
SickBikeParts.com has them.
I have mounted a brake lever on the left along with the clutch before, on a GT1 bike with 2 V-brakes and a hub brake.
The stock setup was a joke.
Not only was the band brake pretty much useless it was tied to crappy dual pull lever that didn't self adjust and the other brake lever on the left.
The right got a TT hand brake for both V's, and the drum brake got a left lever pointed out of the way as kind of emergency brake you never use.