Replying to Balance

So I got into park around last year and I have progressed a lot. The only issue I'm having is rails. I seem to be slipping out a lot, sliding off early, or I go over the bars and hit my ribs on the rail. This is mainly when I'm hitting harder features.

Anyone have any exercises or any way I can improve my balance on rails? Help would really be appreciated.

Also on my 270s out I'm having a lot of trouble being consistant. Help on that would be appreciated too.