Tom, here is a sideshot of my car
20x10.5 (+45) = 3.95 front space, 7.55 backspace
20x9 (+36) = 3.56 front space, 6.44 backspace
Use my rears as a guide. You don't want it sticking out further - so that's what nearly a 4.0 inch front space looks like. And it looks better than it really is because my tire is stretched. If you go further than 4.0 fs in the rear, it'll be retarded, so the 10.5 inch rim is a dealbreaker. I think the 9.5 will fit pretty good, but now you gotta match the fronts to it. Keep in mind our front tracks are 1 inch wider than rear, so you want something about 1/2 inch less front space on the fronts in order to be even with the rear. That puts you at 3.11 front space - or the 19X8's.
19x10.5 (+27) = 4.67 front space, 6.83 backspace (retarded)
19X9.5 (+41) = 3.61 front space, 6.89 backspace (thumbs up)
19X9 (+32) = 3.72 front space, 6.28 backspace (retarded)
19X8.5 (+45) = 2.95 front space, 6.55 backspace (retarded)
19X8.5 (+20) = 3.95 front space, 5.55 backspace (retarded)
19X8 (+35) = 3.1 front space, 5.9 backspace (thumbs up)
If you want to double check the math (to keep me honest), figuring this all out is pretty easy. Every rim's advertised width is REALLY 1 inch wider because they don't account for 1/2 inch at the front and back of the rim for the bead. So the true centerline of a 10 inch wide rim isn't 5 inches, but 5.5 (11/2). Once you know the centerline, you can figure out the rest from offset. +45 for instance is divided by 25 to convert to inches. +45 = +1.8 inches. On a 10 inch rim, you start at the 5.5 centerline (remember, it's really 11 wide) and add 1.8 to see 7.3 total backspace. Front space is just subtracted from the width (again, not 10 inches, but REALLY 11.) So 11-7.3 is 3.7 front space.
The key is if you know how an existing set of rims already fits on a vehicle, then you don't have to visualize. Like with my car you can see how much 3.95 front space is in the rear, and how much 3.56 front space is up front. So those 19's I selected earlier would sit about 3/8-1/2 inch further inward. Which is a good thing IMO, cause then you can run a tire with a little buldge and still have it fit within the wheelwells.