usually, “most of the time”, i’ll have a no11 tight to the eye of the float, then a no9 or bigger around 4 inch above that depending on wind, have never had to go above a bb in size though!
Works really well for me!

Hi, a good tip i picked up from a john arthur video is when
shotting your floats up is to shot them to the base of the tip,
then add number 10 shot until your float is dotted down.
then when the conditions are perfect bring the shots to the base
of the float tip and when conditions get worse move the shots up halfway
between float and pole tip to create back shot.

i back shot a lot of rigs…..started doing it on the cut after watching polly vids years back excellent way to get the float the way you want it…but i have started to do it on pellet rigs lift the back shot and the float raises an inch lower it back down and it goes back down again….just my way of lifting and dropping i suppose

i back shot all the time when conditions are tough,,, always use something like a no1 or bb in general
8’s 9’s and 10’s do sod all,,
next time its windy, put a few of em on a bit of line and hold em up,, you’ll see what i mean,, you might aswell not have anything on the line !!!!
although they do have a use for light surface skim, and being incorperated like some have said into the floats shotting capacity !!!!

On commercials i tend to use either 2 to 3 no8 back shot just because you are using a shorter lash.on natural venues when its blowing its cut off i use anything front a bb to a swan shot placed halfway between tip and float.beware if you are new to this take care when shipping out as it can lead to tangle.the more you do it the easier it becomes.some people paint these back shot a bright colour so they can be seen.i find if you use a spray bar to position your back shot a couple of inch below the surface you have perfect presentation even in the worst of winds.