Hmmmmmmmmmm, not sure to be honest. I didn't realise there was a course and a fine but it does make sense that there is. However, If the bait you are going to make is intended to rely more on it's attractors rather than the food value then I would go for the course because it'll help water ingress and the flavours to flow out of the bait. If you want a tight bait that lets the attractors out over a longer period of time then the fine might be a better option.
It would also depend on what other ingredients are in the mix too and how course or fine they are. Too many course ingredients and the bait tends to dry out quickly when rolling and not bind too well. This can also lead to baits splitting when sticking them out. The finer semo would more than likely assist binding such a bait together.
Something else to take into consideration is the lake you intend to fish. If the lakebed tends to be smelly silt then a bait containg course ingredients will suck those smells into itself far more easily than one with finer ones.
There will be other things to consider too that escape me for the time being. Hope some of this makes a bit of sense and helps fella .