Yeah, I've seen a good number of posts from folks about the BBB coils only lasting 2-3 days for folks. As long as they are primed properly, not overdriven too high on the power and not let run dry, I'm stumped. Even with a dark/sweet juice, this seems like a really short time.
I've been through quite a few of the Q2 coils in mine (0.4 and 0.6 ohm) and I get 4 weeks of use, but I'm using unflavored juice. I'm about 20 mls/day, so get about 500ml of juice from a coil typically.
You could try the recommendations on the BBB RBA above. I've used the RBA a few times and no troubles. Keep in mind that if you buy the SMOK RBA, that the Baby Beast and BIG Baby Beast tanks need a larger glass piece when used with the RBA.
The RBA kit they sell is for the original smaller BB and comes with the glass for it. Since you are using the BIG BB you will need to buy the RBA kit, and the glass for it separately. The glass that comes with the RBA kit only works with the original/smaller Baby Beast tank. I believe kidney puncher sells the RBA glass piece for the Big Baby Beast and then you can buy the RBA kit wherever.
So if you try this, here's the RBA kit. RBA works with your tank, but doesn't come with you glass piece for larger tank:
Smok TFV8 Baby RBA Head
They also sell the glass piece needed for the BIG baby beast:
TFV8 Big Baby RBA Replacement Glass
It's confusing, but you will need BOTH to use the RBA with your tank. Many folks only buy the RBA, and you can't use it without the glass. RBA comes with the glass for the smaller BB tank.
I'm the same way as you, buying multiples of something I like. I would suggest NOT getting multiples of the RBA/glass if you decide to try this. Just get ONE and make sure you like it first. It vapes better by far than the premade coils in my opinion, but some folks have issues with the RBA leaking. I never have, maybe I'm just lucky.