Well, h-BN was proven to be the best in terms of dielectric for graphene, getting the carriers to transfer through the graphene layer almost without any dissipation, reaching the mobility limits up to 1.000.000 cm2/Vs. I believe the noise does scale similarly.
the choice depends of the sensing principle or working principle, and the working region (subthreshold, close to threshold, or above-threshold regions) in which graphene-based sensors operate.