I load for my 7.5" SRH 454 Casull I work my loads up until they start to have sticky extraction then back off 1/2 gr which results in a very accurate safe load every time I also use a Lee factory crimp die...
You can over tighten the die and give to much crimp that makes your pressures jump so be careful not to over crimp, basically with jacketed bullets I give only a 1 1/4 turn adjustment and up to 1 3/4 turn adjustment with cast bullets.
Here is some of my load data that is safe in my guns and results in perfect extraction everytime, I am using Rem 7 1/2 primers and Winchester brass.
38grs H110 with 240gr Hornady XTP-Mag's = 1880fps
30grs H110 with 300gr XTP-Mag's = 1585fps
31grs H110 with 300gr Speer Gold Dot's = 1625fps
27grs Lil-gun with 355gr Beartooth or 360gr Cast Performance WLNGC's = 1525fps
24grs Lil-gun with 395gr Cast Peformance WLNGC's = 1420fps
23grs Lil-gun with 405gr Beartooth WLNGC's = 1400fps
I also have a 4.25" SRH 454 that I use all of the same loads in it but reduced the 405gr loads to 1200fps with 21.5grs Lil-gun the 23gr load above give 1330fps from this gun but give me quite the wrist twist so I don't shoot them that often.
Hope this info helps it did take me quite a bit of time to work of the loads listed above.
I have heard people complain about the expanding of the cylinder when top loads are fired in SRH's resulting in cases being hard to extract, I don't see this as a disadvantage I see it as Ruger gave me a built in pressure gauge for safe pressure loads.