I have to agree with what is said about this, you can't possibly expect somebody with 30 members to be able to compete with a larger Guild and to have someone say that maybe you should join a better Guild as preposterous... Some of us don't want to be in a gigantic Guild. We like things the way they are and we do well. However when you consider the amount of resources that Battlegrounds takes then you should at least make it a Level Playing Field.
Sure I can expect that it's possible. It depends a lot on who the larger guild is, how active they are, etc. The point of how it's setup that every guild from a 1 member one to an 80 member one is competing in the same pool and potentially eligible for the largest prizes. If 1 player guilds were only paired with other 1 player guilds it wouldn't be very fair to make them eligible for the same guild rewards as a coordinated active 80 player guild. Hence that 1 player guild needs to show they can actually beat 80 player guilds to get there. In this extreme, it may seem unlikely - but 30v80, that seems quite plausible.
The majority of the reward comes from the league you're placed in. If you're in the top 2, you're on your way to getting to a higher league (though it might take some seasons). If you're in the bottom 2, you might be falling out. if you're in the middle of the pack, you're probably just staying put - eventually this is where you should expect to find yourself. Don't fret that you're not "winning" the round.
There will always be occasional mismatches. Guilds get stronger and weaker and it takes time for their rating to adjust.
My 3 servers for context:
Houndsmoor - inactive guild of 3, up against guilds from 1 to 64 members in Silver. winning so far.
Langendorn - active guild of 13, up against guilds from 2 to 63 members in Silver. running away with it.
Yorkton - active guild of 5, up against guilds from 3 to 38 members in Copper. winning handily.
So no, I'm not part of 'big guilds' myself, and I absolutely want the possibility to compete with them in future weeks.