Mixing by weight is probably easier, less messy and less hassle.
But me and these beakers, well, we'be been through a lot you know?
When i picked up my first bottle of VG by the cap without tightening it they were there to see the mess I made.
When I left my bottle of DiyOrDie on the halogen hob, forgetting I'd just turned it off, they survived the fire with me.
When my dog decided he liked neat one shot concentrate and would grab a bottle for himself then promptly salivate pancakes all over the kitchen they were there.
Me and these beakers go way back. We've been through too much together. It'd be like swapping my kids.