The bullet with the largest meplat in a reasonable weight range would be your most effective option. The Lyman 311440 or Ranch Dog would be fine examples.
The Beartooth offering sure seems as if it is the Lyman 311041. Best bet would be to call and ask.
It is generally not desired for gas checks to extend below the case neck. In my opinion the RCBS 180 will be less than optimal in .30/30, but I don't see why you couldn't make it work.