Brewer,
Your bolt action allows much more flexibility and may help with feeding the 200 as compared to the typical AR.
My 357AR Max did very good with my custom 200 NLG (2 moa at 200 yards), but the gun seemed to like this bullet better pushed real hard (2050 fps and more pressure than my primers were happy with).
Hopefully you can find an accuracy spot closer to you desired velocity.
As for diameter, with PC there is no reason to go so big with bullet unless you have slugged you barrel and it is bigger than typical. If you have other sizers, I would go closer to somewhere between groove diameter + 0.0005" to groove diameter + 0.0015".
I ran Quickload with the Lee 200 and Unique to give you an idea of charge vs. speed.
Code:Cartridge : .350 Legend Bullet : .358, 200, LEE C358-200-RF Useable Case Capaci: 24.853 grain H2O = 1.614 cm³ Cartridge O.A.L. L6: 2.070 inch = 52.58 mm Barrel Length : 16.4 inch = 415.9 mm Powder : Alliant UNIQUE Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time % % Grains fps ft.lbs psi psi % ms -50.0 34 5.00 985 431 11440 1108 100.0 2.074 -45.0 37 5.50 1043 484 13488 1200 100.0 1.924 -40.0 41 6.00 1098 536 15692 1291 100.0 1.796 -35.0 44 6.50 1151 588 18050 1382 100.0 1.688 -30.0 47 7.00 1201 641 20563 1472 100.0 1.596 -25.0 51 7.50 1249 693 23231 1562 100.0 1.515 -20.0 54 8.00 1296 746 26054 1651 100.0 1.444 -15.0 58 8.50 1341 799 29034 1739 100.0 1.381 -10.0 61 9.00 1385 852 32173 1826 100.0 1.324 -05.0 64 9.50 1427 905 35475 1912 100.0 1.273 +00.0 68 10.00 1469 958 38942 1998 100.0 1.226