The only chaining I can do really in VI is fish chaining,
I haven't been lucky with actually using Pokeradar.
I've tried using Gen IV's swarm because... you know swarms are more common and thus the perfect targets for chaining, no such luck here.
With the decoy patches, it's annoying, not as annoying as the fact in Gen IV you had a way to count your chain onscreen and in VI you have to memorize the times you've encountered a Pokemon.
Otherwise, fish chaining is the easiest, doesn't have a lot of targets... but... it's interesting.
I'm pretty sure that decoy patches never occur in the patches four tiles away from your character, which is another reason to select the shaking bushes that are as far away as possible. Chaining by fishing definitely is easier though.
To check where I'm at in a chain while using the radar, I just count the number of times certain moves have been made by my lead Pokemon (and then add any Pokemon that I've caught while chaining to that count).