Without an OS map base I don't really see the point of this. I agree that the off road path network needs promotion (and maintenance) but I don't think this is the best way of doing it.
I think schools located near to the network should use their nearest off road path for cycle training, helping children learn to cycle in an off-road environment and bringing the paths a wider audience.
Perhaps a mass-participation cycle event (e.g. Pedal for Scotland) could use an off-road path as part of its route - bringing it to the attention of a huge potential user base.
Fancy signs are a magnet for vandalism - I think simple signs based on the NCN ones would be best.
Money for cycle promotion and infrastructure is going to be really tight over the next few years and it is a real shame to see anything being "wasted".