I had a Model 8 .32 Remington barrel assembly and used the Hornady 170 grain .321 as well as the Speer bullet and crimped on the bullet cannelure.
My older Lyman Reloading Manual lists a Max OAL as: 2.525
These worked just fine imo, but they are a bit longer then the factory .32 Remington load, with the Speer bullet load oal being a bit shorter then the Hornady. I used a .30 Remington as a guide as I have some Winchester loads in .30 Rem.
.30 Remington Winchester Silverttip: OAL: 2.508
.32 Remington Grafs brass Hornady 170 grain .321 bullet: OAL: 2.565
.32 Remington grafs brass Speer 170 Grain .321 bullet: OAL: 2.534
load data: http://stevespages.com/321_3_170.html