RE: What is a basic 450 size electric?
If you want BNF, then Blade might be one of your only options. You may do some surfing of the Googles and find a company that builds up different helis that are pretty much RTF or BNF or PNP (meaning all you need to do is install your RX and battery and go fly).
Ive never bought anything "heli wise" that was over 100 size that you didnt have to put together and do all of the adjustments. If you find you are faced with this as well...I suggest skipping the 450 size for now and go in at the 500 size or even 600.
I really do suggest the 500 though. It really doesnt cost that much more (if you are buying a clone such as an EXI (what I own) or copter X or even whatever 500 Hobby King sells).
The replacement parts for the 500 arent that much more than the 450...and it flies so much better for a new CP flier.
The 450 is like a hummingbird on crack! lol I can fly my 450, but I can fly my 500 much MUCH better. Plus, its bigger in the air so you can see it a lot easier and fly it out a little further than a 450.
Unless you have a very limited space to fly in...the 500 is all around the better heli to have. And even though I have a back yard large enough to fly my 450 in...I never do because I dont want to crash into the house. IF the heli gets out of control...it sometimes takes a few seconds to get orientation back and save a crash. In limited space...you simply dont have 2 or 3 seconds before its going to be smashing into something. Hopefully that something isnt you or a bystander.
Goodluck, and above all be safe!