I found that I knew more than the guide when purchasing my GW. That being said, I had researched the heck out of it and knew exactly what I wanted. I don't think they include/push this feature to the guides much at all because it was a lot of misinformation or flat out incorrect information I was initially given.
In my case, I already had a June UY, but wanted a December one for my week 50 guarantee. I am still a bit sore that the race week feature came out just a few months after I purchased - I would have loved one of those (for the flexibility - I am not a runner lol)!