Which to use? Grado Sonata or Ortofon Bronze


I have 2 cartridges - a Ortofon bronze and a Grado Sonata and can't decide which one to use. My set up is a Michell Gyrodec SE with Tecnoarm into a VAC pre-amp and a pair of MC275 tube amps. I know nothing about cartridges, etc and I finally caved in and a turntable technician is coming over next week to set me up and I need to tell him which cartridge to install and tweak.

Thank you for your advice.
Both are excellent cartridges.The Grado has a "rounder" sound while the Bronze is more detaled.I prefer the bronze.