And by the way, downtube shifters become second nature quickly. No, they'll never be as good as STI/integrated/brifters in their ease of use. But you'll enjoy using them.

Stem-mounted shifters, to me and many others, are unwieldy in comparison. You have to bend your elbows the wrong way to make them work. I've converted two old bikes now from stem- to downtube-mounted shifters. Never regretted it. And the downtube shifters help people to understand that you're riding an old classic.