welding question

I almost feel stupid typing this question but I need to know.
I've got about a week before the body is done and I've decided to go w/power brakes.
My question is this; Do I need to disconnect the battery or any other vital equipment before attatching my trusty little wire feed welder to the frame? I ask this because I really do not want to have to jack the baby up and try to disconnect the battery. I was stupid and forgot to install the cut-off switch, it's still on my bench.
Let me sneak one more in here, Is the power booster on a '95 the same as a '91?
Thanks in advance,
Rick