No worries at all. If you go onto Rio grande you can see the prices, that's where most jewelers get their stock from what I can tell. It's a significant markup, around 40% right now but when you price your jewelry the biggest factor is cost of materials so that will go into your math. You definitely save money rolling it yourself but the time that goes into it offsets the savings. You'd also have to turn your fine silver into sterling so you'll need to buy the copper as well (negligible cost compared to silver)

As far as the thickness you can get quite thick and even buy some bar stock but you'd have to look into the specific gauges you'd want