If you’re seeing better with a 30mm scope than a 1” in low light, id wager there’s other things going on with glass quality, coatings, or objective....than just another 4mm of metal tube diameter. The interior lenses are usually the same size between the two. Doesn’t take much scope to see past legal, but there’s off-brands like Trijicon
(and others) that’ll blow the most expensive swaro (or Zeiss or S&b) out of the water for a ‘low light’ scope. Sure, they eat up batteries, but it’s not that much more expensive.