Toner transfer does work well, even fine traces. The biggest problem is the copper needs to be super clean. After removing the oxidation from the copper, you will want to make sure its clean of any oils (like finger prints). I use acetone, its a cheap solvent, which also does a great job removing the toner after etching (or botched transfer...). I'm guess in finger prints on the toner image might be just as bad as on the copper, just be very care how you handle the surface you wish to bond. I use a laminator, and get great results. American Science & Surplus has a inexpense well built 4" laminator for around $25.00, which is fine for most of the boards I do.