Try this- http://redding-reloading.com/tech-line-a-tips > Bushing selection
Super easy... I use the .224 on everything (Rem,Win and Nosler brass). I prefer a little more tension (loaded rounds average .226+) with bullets seated off the lands...
A new barrel may be prone to copper fouling. Both of my 204's (Savage 10 predator hunter max-1,Ruger 77) were. I use Barnes CR-10 copper remover.
I have also found bullet seating to be a huge issue. I keep mine at about 2.30". For me, couple thousanths off the lands was too inconsistant.