yes he seems to be hit and miss, I was there last week, Didn't look like he was there ... plus his parts machines are at his home.. I needed a round needle plate for a 28. he brough some in. about 3 months later I stopped. he price was $1 each LOL...
again it's worth going just to see a real live singer #7 That thing would sew car fenders.
with the care you've taken on your adapter I'm sure it will work just fine... I did teh same on a take up lever 20 yrs ago, it hasn't fail yet. The machine is a singer 16-188 thats a 1916 / 18 ? walking foot, Brazing is alot stronger than people think..