I finally built the first prototype circuit on a perfboard.

For those who want the method, here's how I do it :

• first, I draw the layout in Designspark (free PCB software) with 2.54mm spacing everywhere. I try to draw a single layer circuit, with minimal bridges on the top layer.
• when I'm happy with the design, I print both sides on paper (bottom side mirrored). They are my templates.
• I glue the top template on my perfbard, and punch every hole
• I solder the bridges on the top side, and then the components / pin headers
• when it's done, I solder the bottom layer tracks, following my mirrored template.

Here is the result, not too bad for something built on a single rainy day (template PDFs are in the project files).

Now, I'm looking for someone to show me how to export a working gerber from Designspark...