When glassing 2 parts together, example:windscreen to deck or bulkhead to hull:
1- how many layers should you use?
2- Is the 1st layer wider and you step back the next layer, or is the 1st short and the next wider? Or does it matter?
3- How wide are the layers?

Yes

Sorry to be a smart azz but it is hard to anser that question. Get us some pitcures to work with.

No problem about the smart-azz thing. I didn't start anything yet so there's no pics to show, just general questions. If your adding a bulkhead for added stength to the hull how many layers of cloth would you use? How far would you tab it in each direction(right angle where the bulkhead joins the hull), and would the overlapping layers start wide and get smaller or short and get wider?

I did the same width on mine and just staggered them a couple inches. You do not have to go real far from what I have been told only like 4 inches on each side. You do not want the tabbing edges to end in the same location. Radius the corners it is stronger. Use a filler to accomplish this.

Each layer should overlap the one under it. The amount of cloth layers will depend on the thickness of the cloth and strength.

What about the fit of the piece you are adding? Should it touch the hull - snug, loose, or be spaced away? Should the added piece be 'glued' on, or only use the tabbing to attach it? I've read references to hard spots and distortion. What's the right way?

I'm guessing the thicker the cloth the less layers needed.

It's good practice to add piece of radiused balsa between your bulkhead and the side of the boat, this helps prevent sheer and tear away.

If you go directly to the side of the boat the likelyhood of it pulling away or sheering the glass is higher IMHO>..

You can also make your radius with Micro Balloons or even better Cavasil (sp)