Please consider making a themed tournament where you pick the themed creatures you want to play and battle others against the same and other themed teams. All would be set to level 26.
In the example below after entering the tournament screen you would pick which theme you want to play. In this example I have sauropods. You would need to have a full team of 8 sauropods or sauropod hybrids in order to battle. Poking on Creatures would show what can be used on this team.
Rewards would be instant and based on the themed team that is being played.
All won matches give 100 coins plus the the chance for the following:
50% - 100 Common Theme DNA
30% - 50 Rare Theme DNA
15% - 25 Epic Theme DNA
4% - 5 Legendary DNA
1% - 1 Unique DNA
If you played a team of raptors and won, you would get some form of raptor DNA. If you played carnivores, you would get some form of carnivore DNA.
This is an example of more basic creatures but you could have teams of bleeders, counter attackers, evaders, ground bird types, fliers, crocks and gators, animal types, stunners, swap in attackers, immune. A tournament of this type with instant rewards for playing specific types of creatures would draw many to play in order to hopefully get some well wanted DNA and even a chance at a few legendary or unique DNA.