I don't think it's a great idea to give an M.E. an uncompressed mix with the intention of him/her compressing it. If you think the concept of bus compression is valid, you should do it on your own. Even a very small amount of compression will change the relationship of the mix elements. If you put it on early in the mix process you can get the glue, density, smack, whatever you call it, and adjust levels within the mix to be what you want them to be. If you get perfect levels and then add compression as a separate process, it can easily change things for the worse. If you end up getting the exact mix you want without compression, the M.E. should be instructed as such. Then the M.E. can use their judgement about how best to preserve the quality of the mix that is a result of using no bus compression. I have one client every now and then that will tell me, they have not mixed with stereo compression, but they want to leave that up to me. It usually works out OK, but I always have a sense of trodding on ground that wasn't meant to be disturbed in the way that usually happens. If you are new to compression, have your M.E. give a quick listen prior to mastering and give a little advice about what they hear happening, and possible ways to achieve a better result.
Dave