I recently installed Rizoma Irides front and back on my V7 III Racer. No resistors needed. As long as I had both sides connected correctly, flash rate was same as the OEM blinkers. If one side was not connected correctly, the other side flashed twice as fast. Actually, that was a useful test that helped me catch a loose connection within one of the bullet connectors. But once all was connected correctly, I didn’t need resistors to get the correct flash rate.
When you say both sides to you mean left and right rear / left and right front? Unfortunately I don't have the mounts for the front iRides just yet so I'll only be doing the rear pins for now. Think that'll cause issue?