The instructions have recommended setting for the S-25 (silver springs & no set screw) The th K4.6 (gold springs & use set screws).
I started to post this same question earlier this week but ended up going with the settings for the K4.6. I have a Wasp .26 & so far it seems to be fine. I think it's engauging a little earlier than I'd like but it might have something to do with the gearing I'm running. It's higher than I'm used to but I couldn't find anyone with a vented 15 or 16 tooth clutch bell in stock when I placed my orders.