THe only caveat I would throw in there is make sure the skills make sense - no +20 hides for 1st level rogues!
I do essentially the same thing Henry does. Don't sweat the details. I also use E-Tools to make up various flavors of sample low-level mooks. Well-armored 2nd level warriors? I got some worked up and saved. 2nd lvl Ftr/2nd lvl Rogue swashbuckler pirate types? I got some worked up and saved. I can just pull out a statblock and copy-n-paste it into my Session Prep notes. But if I have to inprovise a 4th level fighter, for example, I can say off the top of my head that he'd have around 28 HP, a +7 attack with his longsword, and do 1d8+2 damage. No one will ever know I just did that in 5 seconds in my head.