I'm fine-tuning my SG-3. The ring-cylinder adjustment looks good for letters, per the manual's guidelines of using a folded sheet of paper and testing the pull with a typebar firmly held up to the ring. The impression is nice. 

That said, the period and comma impressions are huge (and the comma doesn't look that far off the period); the apostrophe is similarly large, and the underscore slices thin paper stock clean through. I'm using the Avery laminate backing sheet that Pete often suggests because the platen is concrete-like. 

Some typewriters have a little limiter for keys like period and comma so you can adjust their pressure differently than the other keys. Is there something similar on the SG-3?

If not, any other suggestions?

I've tried cranking up the touch control but that doesn't change things much (other than give my fingers a good workout).