It depends on the depth and flow in addition to what you want to do with the float.
If you want to inch it through and use a float such as the cralusso bubble, assuuming I’m using a 6-8g floats in 8-12ft of water with a strong flow, (just to fast for the stick), I’ll have the ollivette 6-12ins off the deck with approx 2.5ft of line to the hook.
Shotting will be a string of doubled up No 8’s between 3 and 6 ins apart, (flow will dictate how close the shot are and also how close I have the ollivette to the bottom.
My hook length will be 8-10ins without any shot on.
With a proper flat float such as the cralusso Torpedo or the Sensas Flat floats where I want the bait nailed to the deck , the ollivette will be 4-6ins off the deck with 2-2.5 ft of line below. The shot will be doubled up as above but will be between 2-4 ins apart and can range from 8’s to no 4’s depending on flow.
It is to a certain extent trial and error and if you’re fishing tight to the float with it nailed you can miss a lot of bites if your shotting is incorrect. You can also get frustrated especially if they rattle the elastic/pole tip and you can’t sort it out.