What is the maximum thickness of granite that my faucet can be installed on?

All of the Kingston Brass faucet specification sheet outlines and displays the measurements for these dimensions. As referenced in the below diagram.

It is recommended to take into account the thickness of the retainer nut and the thickness of your deck/countertop. The retainer nut below is to secure the handle, spout, or sprayer to the countertop, and they are on average ¼” tall.

Typically, you would need less than the indicated measurement to tighten up the fittings against the deck, therefore subtracting ½” to ¾” to be safe, as a result 1-1/8” is the max clearance for this spout assembly installation below.

Faucet below: https://www.kingstonbrass.com/product/kingston-brass-gs2798glbs/

Link source for below: https://media.kingstonbrass.com/pdf/technical/specs/kingston-brass-GS2798GLBS-spec-sheet.pdf