Although the inner stem took me two weeks, the outer stem took me only 1 hour!

I could not yet fasten the outer stem to the hull, because that had to be glass sheathed first
The keel was made separately also

The trick was following:

After making the strips, take them all together and bore a hole somewhere in the middle.
Than screw the whole package onto the inner stem at the right position.

Use some ropes to bend the package and to force it into its final position.

This is much easier when you make the first 8 strips a bit longer. You can first pull these 8 strips against the hull and than the remaining 7. This way you can divide the force you have to apply to bend the whole package. (see Pictures)

Bore about 10 holes, one each 5". and pull the strips against the hull.

Mark the hole somewhere in the middle and mark the whole package of strips so you can not mix them up after you unscrew them.

If it looks good, carefully take it off and put in on a table. Put epoxy on each side of the strips and put a screw into the hole somewhere in the middle.

Take the whole package and screw in against the hull again.

Ask somebody to help to bend the package while you screw the others screws through the strips into the inner stem, beginning in the middle and going to one end and than to the other end. For me it worked well to first screw the front and that screw the part going to the back.