Oh Yeah, You're hooked now.
Tubes are actually alive little critters and once they know you're interested, they've got you. They demand involvement, real "care and feeding" kind of stuff. It appears you'd stumbled into their trap many years ago, (like 30) so you've already got lots of usefull experence to build on.
Get a good VTVM and some tweeking rods and have fun!

Rich