As for more specific discussion, I'm not motivated to spend weeks putting together semi-legitimate models of various stimulus efforts, and doing less than that would be pointless. That said, when you talking about crowding out effects and such, you should be aware that economists are aware of these effects, and they are part of the math that sits behind a stimulus model.
The only thing I'll address in passing about the roosevelt recession is that it emphatically did not occur during a period of government stimulus, rather it came at a time when the government was adopting austerity measures and increasing taxes, which is pretty much the opposite of the situation today.
That said, I stand by my original point that proper analysis is complex, and that there really isn't any substitute for it. Anything less is just noise... so let's leave it to the technocrats.