The second problem is, if you want to implement a microstrip design,
how do you get the trace width right? If you're afraid of surface
mount parts, how will you control the trace width to +/- a fraction of
a millimeter? On 1.6mm thick PC board, assuming FR4 with a relative
dielectric constant of 4.75, you'd like to have a trace width about
2.78mm to get a 50 ohm line. If your trace is 3.5mm wide, you get a
bit under 44 ohms, and if your trace comes out 2.0mm wide, you get a
line that's almost 60 ohms. If you can do the PC board
photographically and have confidence that you can control the trace
width to within 0.1mm, that would work. If you're doing it by
scribing the copper and pulling up unwanted copper, I think you'll
have to be working under a pretty good microscope to get to much
closer than a mm of the desired width-- or maybe cut it on a milling
machine.

The problem that you have with FR4 is that the dielectric constant is not
well defined. Your assumption of 4.75 may be ok from one manufacturer and
one batch, but other examples can differ widely.

Jeff