Lightroom Catalog file is the same format no matter if you use it on mac or windows. So if you do some work in the field using your mac and then transfer that catalog file on the windows machine that's fine, however you also need have your images on both the system.
If you consider to have both system Mac then the workflow would be more easy.
Let us know if it helps.
Thanks for the quick reply...I do wildlife photography and travel extensively...the Lenovo x220 primary use is its a lightweight device to load the images from my cards onto a second device and put them in a copy of lightroom so that I can keyword, mark keepers and a few simple edits. I used to do some photoshop work but the screen angle issues makes that problematic....the device is lightweight and easy to travel with...but full editing is its weakness.
The Mac Pro is so widely used and folks do full editing in the field regularly and then export the catalog to their desktop ....my process would be the same but instead of an Apple, I have a specially built beast PC by Puget Systems for photo editing..Have well over 300K images and a high end NEC monitor and will not contemplate swapping it out.....
Now I don't understand having images on both systems if I use the Mac purely for field work and then transition it all to the PC. That is how I do it with the Lenovo now..am I missing something? It would seem once the PC takes ownership of the image, the original on the Mac would be irrelevant...but I am don't want to assume
See what people does when they use two machine to utilize their work, they use an external hard drive and carry it always whenever they go anywhere.
Import Images in Lightroom and keep the Destination as external hard drive.
Also save the catalog on the external hard drive using the file explore/finder.
once you finish your work and go back to home.
Connect the external hard drive to the home machine and open the catalog right from external drive and you will see all your work what you did in a field, you can update your work by importing more images but you need keep the destination is your external hard drive.
therefor, both system will show you the same and identical Images & edits in Lightroom.
In order to have the above workflow, you should both machine as Windows or Mac, because both machine detect the hard drive in a unique way.
In Windows it will assign a letter to the external resources and Mac detect the hard drive through the name.