I decided to gas weld the base. The original Jenny was brazed, had a fold up tab inside the horn with rivets for strength. I felt a simple weld would suffice.
Here's the finished lower horn next to the original. The holes were drilled and the horn was given a temporary coat of primer.
Next step will be fabrication of the upper horns. I made the rest of the pieces today. Just need to weld everything together.
Till the next shop day