You're 180 degree's out, no doubt in my mind.
By lining your timing marks up with the Tab, you insure you're on the compression stroke. Now make sure you're on #1 cylinder, which will be one nearest your intake (close to). By this point you should have enough wiggle room to get her started, and after it starts if you cant set the timing right (out a tooth), you can just pull the distributor up a little bit, twist the rotor then slide her back down. Now you have more room to play with. Also, make sure you pull the little plug out of spout connector thats not connected to anything (just lying there) while setting initial timing.