LOL @ Heartworm town! :D:D
And welcome back, LDD! And congrats on Gastrodon. You should consult Shuko's guide to reach somewhat higher chains. To reach psychotically high numbers, you must be a brat of luck.
My highest chain is 40 Seviper (which could've gone an unknown amount higher had my game not ended my Repel without telling me), which my game didn't record because I apparently didn't save and I reset to reclaim some wasted Repels. My second highest is:
..for my secret shiny. xP Anyone sufficiently clever should be able to figure out what it is. (PM only; don't post responses about it anywhere) I still hate the radar. It breaks your chains for no reason whatsoever. You follow all of the so-called "rules" (which admittedly I can say have improved my chain lengths), yet still your chains break without any results.
Oh, LDD, I finally got shiny Seviper! It was thanks to everyone's favourite shiny attractor, the Pokéradar, but it was on a low chain, so I think it's a "worthy" shiny. ;) My most recent is another Fearow who isn't in my card yet.
And I know just how you feel about "not posting until you get another shiny." I was like that with Treecko; eventually replaced with Abra. I never got one for six months, and you know how that turned out. .__. (I also switched over to MKDS as my primary game, so I wasn't really hunting that much, but I still was on trips and things.)