Good luck, but I think you'll struggle to get enough takers.
Guilds 4-20 are already well established guilds, and the higher members of these guilds who could have
A) the $$$ to spend and
B) the deck to be effective
have probably had the opportunity over time to move into the top 3 when places have previously been available.
Why haven't they already?
Like you and why some guilds have passed up the option to merge with yourself previously. They have invested a lot of time and effort in their guild and probably have guildies that they're quite close to.
Guilds become a bit like families.
However as I opened, good luck !