First time with my DIY studio

I am planning on using my DIY studio for the first time tomorrow by taking some maternity shots of my wife.

I have made a frame from PVC pipe ala Axton's setup to hold up some Muslin I picked up today. I have both white and black. The muslin is a little thinner than I thought it would be....I hope that won't be a problem.

I only have one flash - a 430ex off camera that I will be bouncing into a 43inch soft silver umbrella. I will also be using a DIY reflector made from foam board. One side is white and the other is covered with aluminum foil.

I am a little concerned that if this first run doesn't produce some decent shots that my wife will become impatient with my new hobby (very new) and not want to sit for me again, so I am looking for some advice.

With only a single light (I will be getting an optical slave soon for a second flash soon) will it be easier to use the white or black background? I had planned on the white, but I don't think I will be able to blow it out with only one light.

Also, will my best chance to avoid shadows on the background (if white) just be moving her away from it a decent amount (3-4 feet)?

To minimize my risk of crappy pictures should I go with main light about 30-45 degrees off axis and the reflector near her parallel with the camera line of sight? What is the "safest" setup?

Last one...about how high should the main light be if she is sitting on a stool? Firing down on a 45 degree angle?

Thanks in advance.

Black would be best without another light, but if you make sure that a shadow doesn't fall on it, white would photograph gray if you moved it back a bit. (3-4 feet) to 5-6'

I had 2 lights, but something like this: Simple 2 Light Portrait Set-up

For single light portrait, I like to use lighter BG, as the darker hair and shadow side could be merged into the balck BG.

Main light 45 degree off to the side, about 10-12" higher than the subject's head is a safe setup.

Anyway, do some test shots before bring the wife in. Find out what aperture to use and what power setting is needed on 430 before hand.

For pure white you will need quite a bit of light on the background. Otherwise parts will be white and others gray which I dont like personally.

This is an example with two WL800 at 45 degrees on each side of the subject bounced off silver umbrellas with a snow white seamless paper background. This was actually my first time ever using my lights and background.

Anyway I added 580's to the background to get the pure white after this result. I would suggest going for gray as already mentioned or using balck. Does your wife have black hair? If not your fine!

Same set up with black. Of course you see the issue with black hair and no hair light but it is sufficient.