I have 1 channel with 7,000 subscribers...
another channel with about 1,000 subscribers...
and this channel; ThrillbillyCC with around 100 subscribers *videos coming soon*
but all of these channels have separate email accounts...so you must create separate "identities" per channel
in regards to ToastToGo...
big youtuber's might have separate channels, with separate emails, and even separate adsense accounts...HOWEVER when it comes to payments received from ad revenue all of those separate accounts likely based upon common sense are probably all linked to the same routing and account number for direct deposit into their bank account...of course I am no RayWilliamJohnson or what have you...so don't quote me on that...but I would certainly imagine this is how they have it set up.