i had my 1st 30 and a few other good fish on 20 inch links, i was on a weedy water at the time, over particles as well...tho when i tried it later on in the season and im sure i got done without a bleep, just too many rolling over me to have not had anything...but i didnt really have my head together at the time...with hind sight i think id cleared alot of the weed and short rigs would of scored.
so yeah, definitely think too long can work against you, but does have its place, critically balance settling on top of weed id go for a long link.