Kramer aluminum neck relief

[Unawerewolf]

I am working on sorting out this Kramer XKB20, and I’m having a bit of an issue with the excessive amount of concave bow in the neck. It SOUNDS amazing, but it’s a bit clumsy to play.

This neck has no truss rod and utilizes an ebanol fretboard. I carefully pressed the neck in a CNC brake to get about .048” of relief down to .035”. Still an insane amount of relief. Is there a way to work these necks without risk of the frets falling out? If no, are there any Kramer lumie specialists in the Los Angeles area? Lol

 

[026]

What strings are you using, ie gauge? I expect standard e tuning?
String gauge/tension is the most common way to "adjust" these necks?

I have an aluminum bass with a similar problem. Working with a luthier guy, planning on sanding the neck down to a reasonable relief.