A Gyro Chain is when you reach Level 6 on the chain meter. You'll see "5" and then fill the meter all the way one more time. The chain meter increases each time you make a move which matches gems, and decreases a lot each time you make an Idle Twist (a move where no gems are cleared).
You can reduce your effective level by using a monster with a low level cap; battles will be fought at the monster's capped level.
For both your beast and your opponent, avoid beasts that generate locks (most important) and (if possible) stones. Try to get use a beast with the following properties:
- Ability which clears stones, if your opponent generates stones
- Ability which clears locks, if your opponent generates locks. (But, it's really much easier not to attempt this against an enemy that generates locks.)
- Ability which destroys enemy Ability gems
- Ability which changes all the color of some gems to another color. (This is useful for creating more moves.)
- Not too powerful. (You can choose a beast with a lower level cap.)
I've had the most success taking in an Edomasaur; his Gulp ability destroys stones. I got up to a level 5 chain using Edomasaur without using any items.
Try to save all of your Magic Mirrors for doing a Gyro Chain. (This item will allow you to twist, once, in the opposite direction.) Magick Keys will also be useful if you have Locks on the board. Consider making a copy of your save game, as the game may autosave if you finish a battle; including one where you've used your items.
I recommend going up against Paleofungus because they are strong and focus on healing themselves. There are a few in Level 50 Paleofungi in the Grove of Prey.