The Creo kit came with three "plastic" spacers. But showing how much my local shop knew, when I asked about raising the bars, they were sure that the spacers had been used. The spacers were NOT used when I went looking on my own. Adding them was actually quite easy. Easy enough that I added and removed them a few times experimenting. The guy who sells the metal, machined spacers has a few good youtube videos on working on the Future Shock and spacing. I'm not sure that the metal ones were necessary but I guess I felt buying was rewarding him for the very good videos.
My neck problems go back a number of years. I woke up one morning with extreme vertigo. It felt like a major earthquake and lasted more than a week. A bunch of diagnosis (mri, inner ear maneuvers and "water boarding" never pinned it on anything but possibly a pinched nerve or arterial pinch. If I crane my neck upwards, star gazing, looking at airplanes, etc and on a bike, I get a vague vertigo feeling which can be disconcerting when riding a two-wheeled gyroscope. I added all the spacers and just last week, the stem with the higher rise. I am now almost never on the drops.
As I mentioned in the "twitchy" ride thread, the mechanic suggested that a shorter stem (causing a more upright position) would make the Creo twitchy which I did not want. My other road bikes have head tubes that add INCHES to position me higher or more upright. One with extensions to raise the handlebars. the other is a custom so it was designed into the frame. I've never had a custom fitter but I guess getting the custom bike was close. But as I jokingly suggest, the custom bike was for the custom me, six or seven years ago. My new custom me is now shorter and heavier and older with more cranky parts.
Listen, getting old or older is not for the feint of heart! (g)