I've just found this thread and am sorry to hear of your misfortune.
Regarding steel tubes I would be interested in a set for my Cozy.
Regarding how you secured the upper pin with the AN-3 I'm would be concerned that you will cause wear to the press fit end (on the backing plate) as the gear is operated. Since you have secured the outer point the pin will slide in and out of the backing plate as the L bracket flexes. When I did mine I drilled a coaxial hole through the centre of the pin and used a bolt through the length of the pin. I have a large washer on the outer end to secure the L bracket and have a nutplate inside the spar box to react against. In fact I have a large aluminium plate inside the spar box that covers the full area of the inboard four securing bolts and an additional three for the L bracket. Nut plates are used on all seven bolts.
I can provide photograph if any one needs it.