Live 100 NL, Turn raise with monster draw against PFR - good or bad?

[hezster]

OK, here's the situation:

Live 100 NL - Blinds $2/$3

Hero (UTG - $230) 9 [img]/images/graemlins/spade.gif[/img] 8 [img]/images/graemlins/spade.gif[/img] calls.
2 other callers.
Villain (SB - $100) raises to $20.
Hero calls.
Other callers fold.

Now, let's put aside, for the moment, the wisdom (or lack thereof) of limping UTG or calling 20% of Villain's stack with suited connectors.

Flop ($40): K [img]/images/graemlins/spade.gif[/img]T [img]/images/graemlins/heart.gif[/img]5 [img]/images/graemlins/spade.gif[/img]

Villain checks.
Hero checks.
Hero senses a flopped set and want to take the free card to hit his draw.

Turn ($40): 7 [img]/images/graemlins/club.gif[/img]

Villain bets $15
Hero ??

Now, should Hero raise his monster draw, trying to take the pot right there or should he just take the good fortune of being able to draw cheaply. The answer, I suppose resides in what his fold equity is - or what are the chances that Villain has a set here or not. After all, this is a very common line for someone who has flopped a set to take.

So, I did a little EV analysis, weighing a raise of $35 after the Villain turn bet against a call. In doing so I had to make some assumptions:

Call scenario:

1) Assume that if Hero hits a straight, he stacks Villain (hard to read on board, Villain can't get away from set)
2) Assume that if Hero hits a flush, Villain folds to a river bet (not necessarily true in any sense, but for simplicity sake)
3) Assume if board pairs with a spade, Hero calls $30 bet on river

So, assuming Hero calls $15 on turn,

EV = -(0.66)*$15 {lost} + (0.159)*$55 {flush, no FH} - (0.045)*$45 {flush, FH} + (0.136)*$120 {straight}

= $13.14

Raise scenario:

1) Ruling out AA 'cause I don't think Villain would play it that way, assume that Villain pushes set of kings (or AK I suppose) and folds every other hand.
2) If Villain pushes Hero calls.

So, assuming Hero raises the turn bet to, say $50 (not relevant in calculation),

EV = x*$55 + (1-x)*(0.2955*$120 {hit} - 0.7045*$80 {miss})
= 75.9x - 20.9
where x = Fold Equity

So, for the two scenarios to be equal there needs to be a 45% chance that Villain will fold, which I don't think is too high, but may be borderline.

The question is will Villain have a hand >45% of the time in which he will take this line (i.e. check the flop, bet the turn). I guess it depends on the Villain.

What do you think? Are my assumptions reasonable?