If you read Mark Bulgier's posts about how they used preforms on lugs at Davidson, there was a lot of heat and two torches. I think he recently posted a video. Not that there is anything wrong with a lot of heat, I just can't do it with my setup.

The really small boroscope cameras on ebay are more expensive than the one I got. IIRC, it was about $20. It really did make me a lot happier to see that I had good penetration. I wish I had thought of it sooner. There are relatively inexpensive boroscope cameras available from home improvement centers.

Unfortunately, it seems like I deleted the pics of my plugged dropout experiments, and the blades are now in forks, so I can't replicate.