Homebrew PCBs

Not mentioned so far in this round, is the technique of allowing for 
the side etching of the trace in your pattern design.

Depending on the copper thickness and your etchant chemistry you can 
compensate for the undercutting of the etch resist.

So to achieve 5/5 reliably, depending on the under cutting at your 
place, you may have to set your design rules to 7/3 (1mil per edge 
undercutting)or 6/4 (0.5mil per edge undercutting)

Regards