What are some things that need to be considered when designing a PCB and with tinned traces? (i.e. spacing between other traces, thickness of trace, etc.). Is there a minimum spacing I should have between traces? How much of the trace should be exposed?
according to those questions it seems you are aiming to increase the current handling capability of your traces by adding additional soldering tin on top of your traces, if so this video might be of interest
Specific resistance of tin is factor 8 to 10 higher than copper. If you don't manage a quite thick tin layer, the effect will be rather small.
We see tinned power traces in some consumer PCA, I wonder if the design is substantiated by actual calculation and measurements or if it's just superstition.