Rob,
The Eico 720 was my first transmitter which I bought and assembled in 1967 when I was first licensed as WN9URW. We used it at 75 watts output for I think that was the limit for novices at the time. The manual instructed you in tuning using a 75 watt light bulb. It was a great little rig and I wish I still had mine. I might try to but one again sometime.

Bob
WR9V
Spencerville, Indiana