Wow, lucky you! Or 'smart you', I should say, for having gotten them to grow like that so well. You can cut them just about anywhere, though I'd be careful not to do it below the first branch as they occasionally are funny about putting out new ones below there (I mean trees in general, not Ficus in particular). You can also get in touch with Jerry Meislik if you want, as he's an expert on them, at www.bonsaihunk.us/cultural.html (the website) and very good about answering.

Lucy ,
Thanks for the compliments and advice ! Just a quick up-date , I actually wrapped the trees with the plastic on the tenth, the day that I posted this, and the largest tree already has aerial roots forming ( about 15 or so, as best as I can count through the plastic ...lol ) and all are at least 1/2 inch to 3/4 inches in length ! I can't wait to see them after 3 weeks ! I will definately take pics and post after the " unveiling ".
Many Thanks Again !
Jay

Jay, the only thing about topping is to think about the branch that will become the new leader and it's position on the tree. The other is to cut so that the scar will be at the back and as out of sight as much as possible.

I cutback ficus and schefflera as soon as the day temps hit 90 degrees and the nighttime lows are above 50 degrees; in SE GA around June 1. During the hot season they can be defoliated, stumped, anything, as long as there is time to recover before temps go down below 90 and 50 consistently.

Thanks for the advice everyone ! So, is it best to cut back to a branch ? Or does that really matter , and will the tree end up producing a new growing point ?
The main tree that I'm working with right now is currently still in plastic and producing some nice aerials ! I've got a few coming from as high as 19" up the trees trunk .
I tried wrapping the two small branches as well but, no luck there, they may be a bit too "green" to produce aerial roots yet .
At this rate, I will probably wait until next year to "top" the tree as I seem to be having such great luck with aerial root formation , I don't want to take energy away from that to heal a cut top.
I have really come to find that this is a hobby and artform that does require TONS of patience ! If you do not have it to begin with , you either have to develop it, or go on to something else. haha !
I plan on leaving the tree in plastic for at least 2-3 more weeks yet .
Once I remove the plastic , I will take some pictures of my little project and post them so you can get a better idea of what I'm deling with here .
Many Thanks Again !
Jay

No worry to the health of the tree wherever you prune it.Its really a matter of your taste where you want to stop growth,ramify branching.
Its a whole 'nother story but i had a Ficus nerifolia almost croak on me from lack of water in a spring heatwave-ohh,NEVER let that species dry out-never.
After i watered it,got it to sprout again,it had lost all form..."big" lower branches died,etc.
I said,the heck with it-put it in a large pot to help the recovery,then took pruning shears(yes i did) and just chopped all the sprouted new branches into a basic dome.
NOW I will get selective etc.
The point is, ficus pruning is the least worry to keeping them. Only do the pruning during the growing season-but i think you know that.

That's something I want to try with my big ROR Ficus in the water, a little nitrogen and it pushes very long new branches from the lower part of the existing branches in a matter of weeks. I think it would be a whole new tree if there were 3-5 big arial roots going down into the water.

I may have also found the 'fix' for the alge which has been blooming now that the tree has been living in full sun all day. Was at one of my favorite cafe's and the girl there had just put some very small water lettuce in the pond she has, talked her out of a bag full to try in the pot (which is like a lake for my tree).

If I'm right it should shade the water enough to slow or stop the alge growth, it also looks very nice in there.

Many Thanks once again everyone ! Wednesday or Thursday I will try to take and post a few pics , so that you have a better idea of what I have going here .
I'll also take a couple pics of the smaller banyans as well, a couple are doing very nicely ( I think ) but I'm looking forward to hearing from others on what I should/should not be doing !
Been busy here, still trying to sell this house so I can re-locate to Bflo, N.Y. Between that and work and my night blooming ceres blooming with two flowers any day now , hands are full and busy, busy, busy !
Thanks for thinking of me .!~
Jay

HI..... iam happy to get some information regarding the banyan pruning. i have purchased a banyan pre bonsai.. its just with a single straight trunk with four leaves at the top. its about 30cm height. i want train it for branches and ariel roots. will i get more branches if i cut the top leafy part? . please help me.