Are you 100% sure they were Baptists? What was the original source for Scotch Plains marriage location? I didn't see it on the profile.
I have access to a microfiche copy of The Records of the Baptist Church at the Scotch Plains in East New Jersey in the year of our Lord 1747-. I don't think there is anything else still extant for this time period.
It's a typeset transcription of the church minutes and contains disciplinary actions and a list of members, not exactly births/marriages/burials unless they were referenced in the business meeting. There are no Laytons listed in the membership (it was a small congregation, less than 20 years old when they were married).
I also looked at a couple histories of the Scotch Plains Baptist Church. It was an offshot of the Piscatway Baptist Church. In 1747, there were only seven other Baptist churches in New Jersey (Middletown, Piscataway, Cohansey, Cape May, Hopewell, Kingswood, Hightstown/Cranbury). If you are 100% sure they were Baptists this early, you could look for other churches' records.
New Jersey Project coordinator