I Feel Like my Sliding Genioplasty Was Not Enough Projection?

You could consider a revision procedure to project your chin bone further.

You 6 mm plate could be replaced with a longer one to give you additional chin projection. If done before your bone fragments heal back together the revision surgery would be a bit more straightforward compared with if you wait until after the bones fully heal.

You can read more about sliding genioplasty at my web reference link below.

While there are bone limitations as to how far a sliding genioplasty can be moved, 6mms has not reached that limit. If you feel that it is not enough then the simple answer is that it isn't. I would advise to go back in as soon as you can and move it out to 10 to 12mms which would be the limit of the bone edges and the step plate to do it. This is easy to do at this point as the bone is not healed and would be a relatively quick fix. The amount of chin movement you desired should have been worked out before surgery by computer imaging and x-ray measurements.