Advantage of the mapnik.typ is that it looks like the 'default' osm map. Disadvantage are the ugly borders on (non touch-screen) older units. Have you got an example of another Typ file that looks good on the older units? For my cycling maps I've made two typ files, one for older units with very light grey borders. White unclassified roads are still visible because I use a light green background. If you use a white background, 'white'roads are not visible without border or on a yellow background the tertiary 'yellow' roads are not visible without border. I don't know where Mapniks drawing rules can be found.
If the 0xd works like this on all units, I would translate cycleways to it in the default style. The current 0x16 (brown dashed line) would be for footways and paths that are not (primarily or at all) for bicycling.
0x0d on a nuvi and a Dakota: without a typ file they are thin white lines with "line" as label. On a white/grey background almost invisible. :-( On a nuvi 0x16 are thin grey lines. On a Dakota it's a thicker, grey dashed line, same as unpaved roads. This shows once more a typ file is absolutely needed to keep up with the changes on osm. Regards, Minko