Hi and
to ATP. Whereabouts in FL are you? Pictures are always helpful and it would be great to see the grafted trees you already have. Do you know how old they are? The first few years with mine, it was about as tall as its years i.e. 3ft. tall it was 3yr. old.
I think you are expecting a lot in trying to grow and graft avocado trees yourself. They take from 6 to 8 years to begin fruiting either from seed or from an initial graft (providing the graft takes in the first place). I'm sure you know that a start from a seed will not necessarily produce the same type of fruit that the seed came from. It depends upon who it got pollen from. Avo's are wind-pollinated so it might have been any roving pollen from blocks around . . .
My advice on this would be to have fun trying all your various combinations, but don't set your heart on seeing fruit for years, and then on the fruit being good. Hedge your bet. Right now this minute, go get yourself a nice little 3 or 4 year old tree from a good nursery. The large-fruited variety I had at our other house (also in Sarasota) that was very successful was 'Choquette'. This way you will be enjoying a harvest in a couple of years while you wait for your others to 'come to fruition'.