Double sided is difficult to do on a homebrew PCB because of two main reasons:
- alignment
- toner transfer
Getting things to align right on both sides can be tricky, but doable if you take your time. Transferring of the toner on both sides, though - that can be a little tougher nut to crack. If you can figure out how to align things properly (perhaps with guide holes/marks and a light table?) - then you might be able to "tack down" one side of the artwork, then flip it and "tack down" the other side - then use a heated metal plate and some tongs or tweezers or something to allow you to heat both sides of the board at the same time to affix the toner, then proceed as normal.
This is all speculation, though - I've never made my own PCB before, either, but I have read tons about the process (both toner transfer and UV), and have had some wacky ideas on both for implementation...
