That's a tough call.
Rudy, would you be able to show a picture(with your card board wheels) comparing the -13 and -19 in the front with a stock fender?
i'm sure if you could see how it fits on the car people would be much more clear on what exactly they want.
I cannot since that wheel has been junked a while ago. Basically the difference in the -13 9" and the -19 9.5" is merely on how far the wheel would protrude outwards, towards the fender. Essentially the backspacing is the same at 4.5", but the front spacing on the -13 provides an extra .5" of clearance. This might be nice where the tire mock up showed possible interference at the lower valance. If someone with Watanabes in 16x9 -13 up front could show a picture of their lower valance clearance, that would be very helpful in determining the ideal size.
In any case, this is a group buy, so the idea is going to be to make everyone happy. As of right now the 17x9.5" -19 is still a go on all four corners. The price is still $750 shipped, or $700 pick up for those who live around the Bay Area. The time from ordering to your door is 3-4 months (I checked with the rep. today).