I like working with actual numbers vs. trying to "wing it" where your only view is by pivoting around an object's origin, nudging it this way, orbiting around, nudging it another way, etc. only to launch and find it's not anywhere near where you thought it was. I have spent hours doing this with a single entity, and have given up many times. It's very frustrating! If I know the terrain is at zero and I know the height, width and length of my object, placement becomes a "snap"!
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 8.1/64, GeForce GTX645 (passmark 1898); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 8.1/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics