link-farm or link for me
 

How many index page PR links are prudent? 20? 30? 50? 150?

Say you limit yourself to what you consider to be 15-20 REALLY GOOD trades but others within the chain link to 150 (albeit all of which they may well consider to be GOOD enough)

Is there a self-defeating maximum number of trades (however GOOD) and can you suffer from the effects of perceived spam due to other linked sites' over indulgence?

It's a judgement call.

You pays your dollar and you takes your chances.

Arguably there's a disadvantage to having only 20 links out and trading recips with a page that has 200 links out.

Some people will tell you google is incompetent to single out heavy high numbers of link-farm type linking, and that the more links the better. They point to spammers with 1000+ backlinks from crap sources and #1 positions on good keywords.

Other people will tell you that may be true for a while but sooner or later the whole network will be devalued, so it's not an approach that's sustainable.

And there's tons of other factors...