I know the Earth Spacedock is very large, about 3.8km in diameter & 5km in height. The capacity of this is over 100 thousand people! Are the Lya Station Alpha & Starbase 74, 84, 133 the same sizes? Also, what are the personnel capacity for each Station.
Unfortunately, in contrast to most starships, there is almost no technical specifications for starbases in Star Trek canon. I believe the dimensions and capacity you mention are apocryphal.
Worth mentioning is that Lya Station Alpha and Starbases 74, 84, and 133, are all depicted on screen using recycled footage of Earth Spacedock from Star Trek III: The Search for Spock. Given this fact, we can only conclude that they are all identical in design and size.