My vision of the plant was to have a single trunk with a more tree like appearance but once cut back I'm going to have a lot of cuttings left over that I'm not sure what to do with as I don't have the space or areas of light for more rubber plants so I was thinking about putting the cuttings in the pot around the main steam of the plant to create a thicker truck by using the other cuttings, so several trunks together giving the appearance of a thicker truck while creating a fuller looking plant... would this be possible? Yes, it's possible, easy even, but you are going to get a lot of lateral breaks (branching) from low on the trunk as a result of the hard pruning. Those new branches will serve admirably and look much better as trunks than a bunch of cuttings stuck into the grow medium.
I also have a problem... Where I want to cut there wont be many leafs left on the main steam, my understanding is that a plant needs at least 3 leaves but I may end up with one leaf on the main trunk once cut as the other leafs are curled and I would like to get rid of those so that the plant can spend its energy on growing new healthy leafs. How does this sound? It doesn't sound like a problem.
Ficus elastica, if reasonably healthy, is a prolific back-budder when pruned hard. Even if you pruned a branch back so there are no leaves on it, you should get new branches from suppressed buds in the leaf axil immediately above each leaf scar. Note the bud above the leaf scar facing you just above the low branch growing to the right, and other buds as well. If the top of the
Ficus benghalensis in the image was removed, these buds would immediately be stimulated to grow.
You'll see the new growth in your tree within 2 weeks, but be very careful not to over-water. That is the most critical factor because the amount of water the tree will be using will have been reduced dramatically by the pruning. Use a "tell" as your guide to appropriate intervals. Ask if you are unfamiliar with using a "tell".
Another possibility would be to graft the two healthy cuttings back on to the main steam... probably easier said than done with the grafting... I'd skip the grafting for now. Ficus with finer branches lend themselves to a variety of grafting techniques.
Not sure what this ^^^ type of graft is called. I tried it and it works, but your branches are too heavy for this.
This ^^^ is a thread graft where the branch is threaded through another branch or stem until the cambial tissues merge. The left side of this branch is still attached to the tree
This ^^^ is an approach graft on a maple that has 'taken', so the graft side is now self sufficient while the supply (left) side of the graft has been severed. This type of graft would be appropriate for your tree, but it takes planning ahead to position the branch and establish the graft. Usually, you plan/grow/position the branch to be grafted one year and establish/grow/separate the graft in the following year. A shortcut can be taken if you have a cutting already growing on it's own roots that you can graft this year.
One thing I forgot to mention about the rubber plant was that when it was under the grow light, it was also in a large planter and had a big root system which was severely cut to fit a smaller pot so the plant had a lot of punishment during the transfer. This plant was originally an experimental plant. Did that occur about the same you pruned it? If yes, it is probably a good thing.
I've found plants grow best at 6500k color temperature but I'm going to do some experimentation with some 8000k car fog light bulbs and have these shining on the pothos. 8000k will be very blue and lack almost entirely the warm end of the spectrum (red yellow orange), which might be OK for foliage plants, but not much will want to bloom under them. I have about 45 Ficus, not including cuttings and layers, and I grow under 6000K LEDs. Let us know how that goes.
Al