Well, I'll tell you, I'm in the middle of this project myself, and this is my first time. I was convinced to drop the cradle... It /is/ really easy... the only thing that really hung me up is 3 seized, very very hard bolts. I had to cut two out, and drill out the third... that has been a major pain. But, if these hadn't occured, it would have been increadibly easy. Then when the cradle is on the floor, pull the engine, instead of the transmission. The engine is only held in with 2 bolts beyond what holds the engine and tranny together. the tranny has 6, plus a pair of axles.
This project got expensive real quick though... I had to buy a hoist, and the materials to make a dolley, and several blades for my sawzall... but, all of these I can use again... except the sawzall blades >_>
But, I have no idea how hard it would have been had I gone with it the way you are talking about, I considered it but was persuaded not to. I do know you'll need an alignment after you're done. I won't :P But, I'll have to burp my coolant system, and you won't. But, I plan on dropping the cradle again next year to rebuild the engine. So now it will be stupidly easy for me to do. As I'm replacing all the bushings with aluminum while I'm down there, and replacing all the seized hardware.
I've never done it before, but with a guess, I'd say at least half the width of the Fiero would be a minimum I'd go with to do it. The half-axle on the drivers side is really short, and the transmission is pretty much right there. So you probably don't need a whole lot of room. I know you need to get a floorjack under the transmission to pull it out. So at-least as much room as your floor-jack handle sticks out from under the car. Depends on how clostrophobic you are.
[This message has been edited by Twilight Fenrir (edited 09-23-2010).]