I know in the Republic Commando books, there was mention of MILLIONS of battle droids that were never seen by the GAR. One of the recon trips they figured out some obscene number of droids that were being produced, and figured they could be overrun rather quickly, seeing putting droids together is a lot faster than growing clones.
Plus, lets not forget that Palps was playing both sides, only to scatter the resources of the Jedi, not to really take over planets.
Venator class SDs (Clone War)
Crew 7,400
Passengers 2,000 troops
Victory class SDs (Episodes IV-VI)
Crew
* 5,200
o Officers (610)
o Enlisted (4,590)
+ Gunners (402)
Minimum crew 1,785
Passengers 2,040 (troops)
Death Star
crew of 265675, plus 52276 gunners, 607360 troops
www.starwars.com/databank/location/deathstar/