1970 2-bbl Carter rebuild tips / things to watch or check for a first timer.

If you know someone with an ultrasonic cleaner big enough for the carb, that's the cat's meow.
Captured idle screws - if used on your carb, will make it that much harder to clean those passages. Since it was running OK - might try cleaning without removing those - if present. Sealed screws - similar, but once your remove the limiter cap or the lead seal - most will come out like a normal screw. Watch out for left handed threads on them. If someone here has that exact carb - they'll know.