I've done some Flues from GSI blanks. And another from a stick.
A Flues has nothing drawing it forward except draw boring.
Pitfalls include lack of parallelity in the stock tips that wedge behind the sides. And over cutting the mortices for the safety and hand pin.
When doing a Flues I over-dry the stock and remove the absolute minimum material from every area. It will swell after fitting And you can carefully remove material where it binds or obstructs
Conversely GSI's patterns may be cut too deep under the top strap and you end up having to fill in the mortices area.
So first its the stock horns, then the shoulders for parallel coming forward for stock to action back fit Then it's the downward inletting of the top strap for a tapered fit in the mortice.
Get any of that wrong ie not plumb or square, and the stock will be twisted to the action, leaving a shoulder high and the other below the action side.
From a raw blank there is much more latttude for elevation and squareness than a pretty machined blank.
I have 4-5 Flues to stock maybe we can work through one here
Though I caution, I am no expert. I've just turned some into sawdust is all.
