I'll take a stab:

Stem length:Measure center of the stem binder bolt to the center of the bars.
http://www.parktool.com/repair/readhowto.asp?id=130 (see letter G)
An experienced fitter can look at the geometry of the bike and tell you if a 70 mm stem is too short for handling purposes. Probably yes, but only someone familiar with the geometry and handling characteristics of your specific model and size bike can give you a good answer.

Stem spacers: do you have a spacer on top of the stem now? If the top cap of the head set is flush with the stem (like in the picture above) you cannot add a spacer below the stem. You can swap locations of spacer above and below the stem only. The steerer tube of the fork dictates how many spacers you can use in total. A stem with a higher rise could accomplish the same thing.

Hand placement: you need to have the position set up properly so you can ride in the hoods and move back to the top of the bar for relief.