Soldier coursing on top (brick laid vertical), sill coursing on bottom (brick on edge with a slope...or use Limestone solids supported by your white/gray brick.

We used what our mason called "half in-half out". I love it. I couldn't find a close up of window but this is around garage door and is exactly the same. There is a soldier course at the top where wall meets roof.

I like the soldiered brick that Ironwood B. mentioned .. along with a keystone over each window, will emphasize the curved tops and really dress them up .. especially looks nice with a variegated brick like yours.

Not the best pic here ... but I'm running off to work now!

Some pictures (adding to Ironwood's idea)

Thank you all so much! You have been incredibly helpful!