I do mono backing until there is enough for the braid to catch on, then it’s braid, after that I do a perfection loop knot on the end of the braid into a loop-loop connection with a fluorocarbon leader which has a perfection loop knot on one end as well. This is a little extreme (generally used for dry fly fishing) – it is the smoothest for getting line out and the loop to loop eliminates braid twisting up.
As for the backing lb. test, I generally like to go with 6-8lb, even with reels I’m going to use for lake trout on Superior. The smaller diameter mono catches the braid better and doesn’t slip hardly at all – the backing can slip if it’s too heavy so that’s just something to keep in mind!