Yes I cut the slots on the side brackets out more it will allow the radio to slide farther forward than shown. These are the flattest bolt heads I could find.
You still have lots of adjustment where the Brackets attach to the radio body though. Also don't put the Plymouth decal on the radio face until you are ready to install it for the final time. And... don't forget the locktite!! You don't want any of the fasteners coming loose, if they do, you have to take the whole cluster back out to tighten them! (ask me how I know LOL !!)