Simon
Welcome to the site.
Your question doesn’t have an easy answer, I’m afraid. You are correct that float capacity and depth will play a part in the decision, but so will the species you are looking to catch and the tactics and feeding patterns. A lot of people tend to use shot for floats up to 0.5g, and for this, it’s not very often that you will see anything other than a bulk of Number 8 or number 10 shot and one or two smaller droppers. The bulk can be grouped tightly together or spread out slightly to give different effects to the presentation. Similarly the two droppers can be pushed together 6 inches or more below the bulk to give a “double bulk”, which is a more positive rig.
For floats over 0.5g many prefer to use an olivette plus a few small droppers which again can be used spread out or in groups to vary the presentation. When using olivettes, my preference is to use in line ones rather than pegged ones where a sleeve is pushed over each end to lock it in place. with the in line ones, the line goes through the middle and they can be locked in place with a small show either below it or above and below.
Hope this gives you a starting point.
TF_Man of Kent.
