Cracked 2007 Condor Pista

As I couldn't be arsed paying Condor £415 for a new frame, I went down the following route.

Used a hacksaw blade to get the shim out. It's 60mm long, and glued in.

Removed the paint to see the extent of crack.

Then I drilled holes to stop the crack spreading. Used it like this for a while.

Decided to get it sorted/bodged properly, and took it to Ted James who brazed it up, and added a pseudo lug over the top of the joint.

Will see how long it lasts, but it's better than throwing the frame out, I guess.

Ok so I have a 2007 Ltd Ed Potenza which has the shit shim setup. I really don't want a crack so I was wondering what evasive action I could take. Could I saw out the shim now and just fit a wider seat post thus removing the problem? If so what size post would I need?