For what it's worth, and just my opinion of course, when trotting I virtually always use bulk and a dropper. Occassionaly i'll slide shot around but I usually always finnish up back to the bulk and dropper. The flow and depth of the water will determine how big a float and what shot sizes I use etc. Again "JMO", all that shirt button shotting is just a load of old tosh, it might look fancy but it certainley never caught me any more fish, quite the opposite infact. Most fish on the river feed on or close to the bottom and so it makes sense to get the bait down there asap, you can still hold back to alter the presentation of your bait.
On the rivers I fish that catches me all the species that inhabit them from gudgeon to dace, grayling and perch etc.
The still water method with no shot on line line is great, but, as with other methods it is only productive in the right conditions. I often use the method when fishing on the deck, just float legering really, even loose the float and just watch the line as it hangs from tip, or where it leaves the water with maybe a little slack laying on the surface. It's a method you will need to practice and you will just instinctively know when your getting things right ??.