Would veneers or gum surgery be best if I have receding gums?

When you shift your teeth at night it's stress. A myorelaxing plate is made to the patient to be used at night. To prevent tooth wear. If you have a gingival recession, I advise you to go to a periodontist  the. Ideal is to make a gum graft. Bethe veeners are not indicated when the oatietsn have gum recesition. And also do an appointment with an orthodontist to see how your teeth oclution is  and more with the bruxism that you suffer. 

if you have receeding gums,i do not recommend veneers,because you need to gain the area of receeding gums,and veneers are thin laminates,my suggestion is to have zyrconia crowns,you will be able to make a more aesthetical and even smile,
with Zyrconia crowns,shape size and even color can be done within just a couple of days and you will certainly will improve and have the smile you always wanted.

if you have receding gums and shifting teeth over time, I would consider seeing periodontist or gum specialist to discuss treating or stabilizing the gums first.

I suggest you look into the DNA Appliance and Epigenetic Orthopedics.  Dr Nick Myers in your area is now doing the DNA Appliance.I suggest looking into that before making other decisions.