if it helps

i have .3, .4, .5, .6, .8 E3D v6 nozzles
plus .3 .4 .5 hexagon nozzles

my printer is a i3v 12" with mods listed during test

8mm threaded rods 1.25pitch and deep home turned bronze nuts 4H fit 5120 steps per mm 1/32 micro stepping
Azteeg X5 mini 32bit controller + viki V2 display (ah so smooth had to give it back to my buddy will buy one soon)
makerfarm extruder with custom gears (1/2 the ratio of stock gears) 745 steps per mm
all accel settings to 3000 jerk at 20
speeds limits at 300mm/s 10mm/s for Z (like so much 32bit)

and max print speeds i have found tell a lot
"using cura all speeds matching infill and so on"

matterhackers PRO ABS black 1.75mm (good stuff)
250c
test object
20mm X 20 X 60mm cube 1 prem 100% infill .2 layer height
tweak z adding feed 10% every 5 layers

E3D nozzles (on hexagon hotend)
.3 max was 60mm/s before back pressure lock things up
.4 max = 90mm/s
.5 max = 120mm/s
.6 max = apx 150mm/s at this speed other things might have a part in it
.8 max = apx 180mm/s

i did this test with the E3D 1.75 uni hotend as well
speeds matched hexagon upper almost verbatim with only 5~10mm/s boost with larger nozzles
(larger melt zone so expected)

hexagon nozzles
.3 = 40~50mm/s (had lots of clog problems tossed nozzle in trash a few days later)
.4 = 60mm/s
.5 = 90mm/s

so after putting nozzle vs nozzle i must say E3D nozzles rocked so much less back pressure worth the price and much more accurate sizing
i know the larger nozzles will go much faster with a bigger melt zone and or high temps
but with a i3V printer anything that will remained stable at speeds over 60mm/s is fine i don't really think anyone
with a i3v wants to print faster as the frame starts to move with much more speed