Bill, when you create an object with the Figures library, the dimensions are displayed in the status bar at the bottom, but you have to zoom in if you want to be exact. For example, when you draw a rectangle, you can see the A & B coordinates; A being the horizontal length and B being the vertical. A circle shows the diameter. A polygon shows the X-Y coordinates and length of each section. Unfortunately, the only way to get close to exact is to create a basic object and then zoom in to move some points. For example, when I draw a rectangle, I start at 0-0 in the upper left of the rulers and draw the basic shape. Then I zoom in on the 0-0 point and make sure it's at 0-0. After that's set, I zoom in on the lower right point and move it until I get "close" to the A-B lengths I want. It's a real PITA, especially with polygons and large rectangles, like 30' walls. It'd be so easy if Mixy would expand the Toolbox to allow creation of polygons, other than the baseboard, using coordinates. Then you could just define a 30' wall as coordinates (0,0), (360,0), (360,-4.5) and (0,-4.5) like I can in RR-Track. I realize he can't copy RR-Track and add it to the Properties dialogue, but if the Toolbox can be used to define exact coordinates for the baseboard, why not for regular polygons?
As a side note, I drew a 10'x20' rectangle eyeballing the grid lines. Like you said, it was off by well over an inch on both the length and width even though it looked like it matched the grid lines. So, I went through my process to make sure the starting point was at 0,0 and then zoomed in on the 240,120 point to move it until it was exactly 240,120. Admittedly, this generally isn't super critical unless you're trying to squeeze every inch out of the available space by placing track along the edge of the layout, trying to stuff specific accessories into tight spaces, etc. If you're at a point where a couple of inches matter that much then you're probably trying to fit too much into the space. 
As for text, when you place text, look in the upper right, there you'll see the font and size. One note here is that the default size changes with the zoom factor and it may look okay until you zoom back out, so make sure you change the font size or always add text when in full view mode.
