messing with my case saver today. measured the aluminium, it is .25 thick.
I had tried with lesser skills to drill holes to mount it about 2 years ago and i ended up drilling 3 holes (one extra) to get it to mount, then i always had slight pedal clearance issues with the case where the nuts stuck out on the outside of the clutch arm cover. well i filled those holes with a weld and i am going to try to drill and tap the hole so i don't have a nut or bolt sticking out where my pedals can hit.
Noticed when welding the cast case that all kinds of lovely stuff came up to the surface.