I dunno if it makes a difference. I think everyone has their own way of mixing.
Personally, I use a votive candle holder, glass, to mix my
juice in before I put it in bottles. It's like a small, straight sided, drinking glass that holds just under 4oz. Since I never make more than 60mls of a flavor at a time, 2 oz, this works for me. I also use a small, battery operated, milk frother to mix. You can get them on amazon for about $5. (I'm sure other places too)
Here's how 'I' do it and it's just what works for me and what I'm comfortable with. YMMV
I add all my flavors to the glass, mix for about 10 seconds with the frother, add PG, which as I understand it, is the flavor 'carrier', mix again for 10 sec. Then add VG, mix, then add nic, mix. When the bubbles have dissipated, I pour into my 30ml, amber glass bottles w/a small funnel, cap it and put in the Ultrasonic cleaner for a couple hours. Except for fruit flavors, I only put them in the UC for 8 mins.
Like I said, this works for me.
There has been some discussion about using a frother, good or bad. I tested on my own, made 2-30ml bottles of the same flavor, same recipe, same nic level but using the frother on only 1 of them, hand shaking the other one. Then 2 hours in the UC. The one I used the frother with seemed to be better mixed and ready to
vape after the UC time, where the other still needed a week or 2 of steeping, as they had needed in the past before I started using the frother. Take that for what it's worth to you. I may be imagining the difference, who knows? But I'll continue to use the frother, just because, IMHO, it reduces the steep time.