Undertaking a new weaving project

So now I'm on to a more ambitious project. I wanted to try doing a tapestry but didn't want to afford an actual tapestry loom. I've come up with my own version which I think will work fairly well, and I can at least practise on it and decide if I like tapestry before putting out money for a professional loom. It's constructed from a sheet of masonite, a dowel, and an old weaving reed that was too damaged to use on my floor loom. I cut it in half to provide spacing guides at each end. I started warping it last night and will finish today.

Behind the warp threads is a pattern I had left from my stained glass days (painted glass, actually. I never did the actual glass cutting). I envision basic, bright colours of weft outlined in black embroidery to make the tapestry end up looking like stained glass.

I just need to decide what to use for the weft. Embroidery floss would be ideal for colour, detail, and ease of pulling through the cotton warp, but it would take a ton to fill the whole picture. Yarn is cheaper, probably, and would fill the space more quickly, but it might be too rough to pull through the warp without tugging the strings out of place. Maybe mercerized cotton would be slicker and tug the warp out of place less. Must go prowl around Michael's and see what my options are.

I'll let you know how it goes!