Call-Range Modeling

RE SNG P Tools... On the easy/donkey games (I play the $11s a Party)

Along the lines of garbage-in = garbage-out, the most important element of analyzing push/fold decisions in the late game is putting the villains on an accurate calling range. My question then is: What's a good model for determining call ranges? If nobody has had to show a hand in the last 10-15 deals what can be inferred about any given villain's calling range?

I know that when the villian or villians don't have you covered their call range will be tighter, unless they are "desperate". And that if they have you "comfortably covered", their range will be wider/looser. So how do we define "desperate" and "comfortably covered"? I think stack ratio (villain:hero) of <.5 is "desperate" and >1.5 is "comfortably covered". And that these cause of loosening of around 10 percentage points. So if I apply this as a modifier to their observed VP$IP (or a fraction thereof since calling != pushing) over the last 10-20 hands, would that give a reasonable estimate of their calling range? How would you tweak these values in the model?

I understant that "It all depends". I'm looking for a first-order approxiamtion based simply on recent VP$IP and stack ratios of hero to villain(s). Further modifiers based on number of players about to bust, does a particular villain close the action, etc. make it really complicated. I know.

So please be gentle. And try to stick to a simple model. Replies with "this is useless, it all depends" will not add much to the discussion. Remember this is for "stupid" games, low-stakes on Party.

Thank you all in advance. I hope EastBay replies...