Wondering how what you do on a bar translates to these ie if you can do X amount on a bar can you generally do the same with a log or are they alot more difficult?
There are too many factors to have a set formula, but in general most people can push press more weight with a barbell than they can with a log.
If you are looking for a way to train that will help to increase your log I would focus on incline dumbbell press, close grip bench press, front squats, and some neutral grip standing DB presses.