What freq? The patterns I see in EZNEC aren't even close. If you talking 40, 80 or 160 it's really moot, as the majority of radiation is up (not so much on 40) unless you have LOTS of tower to play with. The null off the ends a dipole aren't really that great if it's low.
The ARRL Antenna Book comes with basic version of EZNEC with a ton of canned examples you can look at, although in my version they're for 80m. EZNEC will rescale them automatically for you though if you tell it what freq you want.