Vortex Defender ST Enclosed Solar Red Dot mounted on Beretta 1301 Chisel Stock

I'm installing a Vortex Defender ST Enclosed Solar Red Dot onto my Beretta 1301 Tactical Mod 2 shotgun that also has the Chisel stock. The stock has a mounting spot for an optical (RDS Mounting Point). The Vortex has a DeltaPoint Pro (DPP) mounting footprint. What is a good adapter plate to get to complete this pairing? I've seen a few on Amazon, but wasn't sure about compatibility.