Re: 300 rum is a beast!!
I have never been very good with spinning turrets. I do believe the practice of spinning turrets is the most accurate way of long range targeting, however, I choose to use the BDC redicals on Nikon scopes. Nikon has a ballistic program like most, plug in your information and it will place ranges on specific spots down the tree inside your redical. I like that much more than spinning turrets. Then all I have to judge is the wind.
My 300 rum is a flat shooting son of a gun that is fun and very comfortable. My 12 year old can shoot it when he doesn't flinch from the boom!! It most certainly doesn't kick anymore then his 270 wsm.
As far as pressure signs go...I have 2 opinions. The first is if your looking for barrel life, don't press the envelope. Find a power node near the top that works and shoot the heck out of your gun worry free. My second is if your gun is built, or your attitude is to pinch every bit out of your rifle that you can, then by all means keep laddering up until those signs show their ugly face. My ladders are by .3 grains. I am very vigilant when I'm creeping up my ladder for the smallest pressure sign. Also keep in mind that some powders are heat sensitive and spike when the powder gets warm. For instance, shooting in North Dakota in the winter verses Texas. North Dakota is -30 and Texas is 50. There is a big swing there.
Big thing is be careful. Nothing is worth blowing yourself up over.