Strad,
Any bulb will work--trouble is, very often the printing on a regular bulb will print through and appear magically in the middle of your prints. Color temp is not a real problem with b/w, actually, especially with graded papers. And you might be able to use a scrungy pad to get the letter off a regular bulb to use as a stop gap. BTW, I used such an enlarger for both 35 and 6x6 and never once changed the bulb position.
Oh, and I also printed with an F/2.0 Rodenstock Heligon taken from an old Retina. It worked. But as soon as you can afford it, get a decent enlarging lens. They're quite cheap nowadays, as others have said.