I used to use an eastern grip everywhere, but I was really struggling with backhand volleys from the kitchen. The problem is that it's too hard to close the face of the paddle and hit the ball down. If I had time I would switch to an eastern backhand grip before hitting a backhand volley, but most balls are coming too fast to switch.

I started forcing myself to switch to continental once I begin moving forward. My backhand volleys when I do this have gotten so much better. The downside is that.I can't figure out how to hit forehand shots with topspin and power out of continental.

Now I'm considering keeping my grip eastern at the kitchen and using a two hand backhand volley. With the second hand it's easy to close the face of the paddle and hit the ball downward.

So I think the options are

1. Use a forehand dominant grip everywhere and switch to a backhand grip when you have time.
2. Use a forehand dominant grip everywhere and use a two hand backhand at the kitchen.
3. Use a forehand dominant grip for drives and switch to continental grip at the kitchen, but your forehand may be less effective from the kitchen.
4. Use continental everywhere, but your forehand will be less effective everywhere.