The speed will come with time & practice. I too prefere a smaller channel. I use 12" & 10" wagtail flippers for 99% of my trad work & a 6" normal channel for any georgians that can't be wfp'd.
I would practice time & time again on one of your own windows to perfect a technique that leaves minimal detailing & no lines. I would try some squeegee off liquid too. Another thing, don't be tight with rubbers, they are only pennies & a new one makes it so much easier for speed with top results. Trying to squeeze the life out of your rubber is false economy IMO. I use pulex standard personally.
It's just a case of doing it, doing it & doing it, trying a few different tools will do you no harm either. Different rubber, channels (stainless a lot lighter than brass), handles, applicators etc.
Personally i would recommend a wagtail flipper, other than that it would be-
Ettore porcupine applicator sleeve
Ettore ledge-eze handle with stainless channel (various sizes)
Pulex standard rubber
Unger BOAB (bucket on a belt)
And for solution- 5ml of GG3 + 15ml of ettore squeegee off mixed in 6ltrs of water.
I don't know what you use now but If you give some of those a go I think you would see a real difference.
