I'm trying to scale a viewport appropriately and am having an issue.

When I'm in model space, I can measure my buildings appropriately (they're correctly to scale), using Engineering Scale. I've sized my page in the print configuration dialog to 24x36 with a scale of 1/2" = 1'. When I create a viewport and try and do a reasonable scale, say 1/4" = 1' or 1/2" = 1', the viewport zooms much farther out than I know the scale really is. I have to use a 1:10 scale or larger to get things to work properly, and I know that that's not correct. Does this have something to do with both the print configuration having a scale and the view port having a scale? Should it be left to 1:1 or something?? Even that wouldn't work.

Help?