ajax

I'm looking for some thoughts on these add on sights. I purchased the Magpul and off of their description they sound like they should work with my chaos extended rail. My issue if any is that they sit quit high, so high in fact that i will need to purchase a raised cheek rest for it. There seems to be a lot of adjustment in the front pin. Has anyone had experience with these sights or the chaos hk sights that could give me some insight it would be greatly appreciated. I tried a search before I started this thread and found nothing. Thanks for any help.