community of dyers

Hello all,
Firstly, this website is such an invaluable source of information, fantastic!

I am very much a beginners dyer. My friend and I are conserving a large (1x2m) textile protest banner from the 1830's, suffering severe weakening and cracks along the painted surface design.
Part of our treatment is the use of a combination of fine denier nylon net and adhesives to consolidate the banner to give it strength. To help the net blend in, we are dyeing it.

We plan to use two methods, the stove top for the background colour (Jacquard Acid - Ecru) and painting for the design (also Jacquard acid dyes in various mixes)

Here are my questions:
1. We are steaming (hopefully) using a vegetable steamer. I know that stove top dying pans are not to be used for food, but what about the steamer? As it is in a package, is it safe?

2. I have read some people adding vinegar to the steaming water with acid dyes. Is this required? It was not described in the instruction sent with my order, though that said, the steaming method was not described at all. I am just confused because the stove top method requires vinegar.

3. Can dyed nylon be double steamed? By this I mean, should the Ecru background dye be applied, steamed, rinsed and dried before the design is painted on? We will need a flat surface to paint the design one, so ironing the fabric would be beneficial, but I wasn't sure if double-steaming the background colour would be detrimental.

I think those are my only questions for now. Luckily we are testing all these things before being let loose on the net, but the time left before the deadline is rapidly running out!

Thank you all for any help you can provide. If you need more specifics I will try my best to help
Holly