Hopefully one of you wonderful boro people will be able to help me

I have been asked to make a commission piece of a spider on a web! (Great, I hate spiders) My customer wants the web in silver (can make that out of wire , no problem) and the spider in black or dark brown glass. I'm thinking that for it to have any chance of surviving I need to make it in boro.
So far I have only had one small step into the dark side

I am on a Minor with one oxy. I bought Pipyr's tut and made a few quite successful beads. I gather that black boro is much stiffer, so......could anyone recommend a colour please that meets my customer's brief and that I have a chance of melting. The amount I need to melt should only be quite small as she wants the whole thing about 3" across.
Thank you so much for any help you can give
Amanda x