There are two 1/4" diameter brass launch lugs on the model. They are set on the bottom, side by side. Both lug ends are pre-cut at a 45 degree angle.
Straight pencil lines were made using my aluminum angle on the short central body tube piece.
I may have mentioned earlier, on lug was about 1/16" longer than the other. You can see the longer lug closest in the picture.
Both will need to be the same length. A metal file and 10 minutes work shortened the longer lug.
The tube was roughened up with 220 grit before the lugs were glued on.
I don't know why but the epoxy lug fillets went on much smoother and required very little sanding. The fin fillets needed more attention.