JohnnySpreadsheet

I find the pure speed of Open to be more exhilarating, and as others have mentioned, Open places higher stakes on stage planning. My brother shoots limited 10 and he is often left with only 1 or 2 sensible ways to shoot a stage due to capacity. The Open guys might use 3 or 4 different plans and get similar results to each other because each method played to personal strengths and weaknesses. I'd suggest really focusing on the smoothest/fastest way to shoot a stage and see if that aspect becomes as much fun as shoving in 4 or 5 mags per field stage. If not, plenty of people are looking for used Open rigs. (Oh, and my brother has an Open gun on order already.)

I also have a STI Steel master that I changed to a 90-degree Cheely setback mount. I love it for all the reasons already mentioned: dot close to bore axis, improved balance point, and no chance of bouncing brass into the port. I have the Alchin thumb rest moved onto the Cheely mount and I am happy as can be, a great setup.

115s for my 9 major shorty. I did a lot of Bill drills and El Prezs with both 125 and 115 Hornady HAPs loaded to same PF with HS6. The 115s gave me marginally higher hit factors. Mostly I noticed less vertical spread on Bill Drill when I really pushed my splits to the .15-.17 range.

While I would not claim the Steelmaster is the ideal platform for 9 major I have been happily running mine with just 1 fail to feed in about 3000 major power rounds. At first all I did was develop a safe load based on the HS6 and 115JHP data shared on this forum by Cocobolo and others. Their info was spot on and after working up I make 168 PF with 9.1 grains of HS6 at 1.160 OAL with Hornady 115 HAPs. I still run the stock recoil master setup but my Gunsmith added two 1/8" holes in a V pattern just inside the front-most Steelmaster slide cuts. The holes made it much less flippy and also much louder. Interestingly it did not seem to reduce velocity by any measurable amount. So, if a Steelmaster is what you have, I say develop a safe load and run it as it sits then thunk about barrel holes. Apart from any major power concerns I recommend an improved extractor if you are still on the stock extractor since the stock ones seem to fail in about 3K rounds for many Steelmaster owners. Happy shooting!