Depending on how wide you smile, its generally best to do 8-10 veneers. 6 is never a great option because the canines are where the teeth in your arch take a turn and you tend to get a shadowing effect of the teeth behind the canines if you don't veneer at least one more tooth past the canine on...
Based on your question, I would strongly suggest consulting with a cosmetic dentist in your region to best assess all your options.Best of luck,James Asaf, DDS
Without a thorough exam or some photos at the very least, it would be impossible to advise you as to the best possible treatment options.Best of luck.James Asaf, DDS