Duramax P003A How to free up the VGT

I keep getting a Check Engine Light (CEL) for P003A, which means the Variable Geometry Turbo (VGT) Vanes are stuck. The first time, I took off the downpipe (PITA) and squirted Easy Off in until the vanes were free (see other video 2 months ago). This time I drilled and tapped two access holes to speed up the process.

This is very hard on the actuator linkage, but the alternative is spending 12-15 hours pulling the turbo and cleaning it properly.

The Dealer's solution is to replace the turbo, which is a $3500 proposition.