Most run 3-18 or 5-25 as far as magnification with 30 or 34 mm tubes and objectives go from 44-56mm. Your budjet will decide what you buy but the EE has lots of options than will allow more bang for yer buck. Make sure the parallax can be ok focused close like 25yards or closer. Try going to a match. People are friendly and will let you look thru their optics. Great learning experience.
Some excellent points made about your findings. Size of the tube does not determine brightness or clarity! Large objectives DO NOT gather light. Nothing gathers light. Optical performance is determined on glass quality,coatings and construction method, Period! Larger tubes are designed for more travel and bigger tubes will always be heavier because of extra material and glass elements which are heavy. In a competition gun the weight is a bonus as its usually centered very close to the balance point of the gun. Most serious competitors guns weight slightly south or north of 20 pounds. Its what gives a steady hold on positions and lets the shooter spot trace. some are even using scopes with 36mm main tubes and gaining large increases in both field of view and adjustments values both in elevation and windage. Hope this helps.Most do run 30mm tubes, some are running the newer 34s. I looked at not only the data but looked through a lot of scopes. Maybe on the more top end scopes, tube diameter might give some advantage, but in my price range, I did not notice the larger barrels to be brighter (I expected they would be). Nor were they any clearer. Maybe a bit more elevation travel in some brands, but not all. They are certainly heavier-weight- than 1". I set a budget of <$500 for a scope; and in this price range I would suggest finding a high quality 1" scope might serve you better than buying an entry level 30 or 34 mm tube. Also pay attention to the reticle, it must be fine enough to not obscure the target. I also considered illuminated and they all seemed to be a bit coarser, so I went without. Parallax is a must; Zero stop for elevation is nice as is center zero for windage, providing the scope tracks repeatably.