What you would end up with is essentially a mix that has pretty much the same physical characteristics as a peat-based soil, but will not collapse as rapidly because of the pine bark's superior resistance to being broken down. I think you'd be happier if you included a sizable fraction of larger bark pieces, but it's up to you. I'm pretty sure you'll find it helpful that you know how soils work and that you've learned you'll need to pay closer attention to how you water when using more water retentive soils; so I guess forewarned is forearmed. ;o) Good luck, regardless of what you choose to do.

Al