[Jonny250]

If you want to make the blades and fit them to existing foot pockets then it shouldn't be too hard; the hardest part is probably getting the angle between the close end and the main part of the blade (my omers have an angle of roughly 7 degrees at the footpocket connection). cutting the profile to fit the pocket should be ok.
Best way would be to make a bottom mould on a flat panel using filler or plasticene, covered with a sheet of polythene. Lay the fibreglass over this, then vacuum bag the lot down. i think vacuum bagging would be important as you dont want a resin-rich blade or it will crack. You can use a layer of peel-ply to further reduce resin content.
ideally you dont want to use chopped mat but use biaxial plies in 0/90 and +-45 directions, or even a triaxial mat so that there is less resin, more fibre. thickness required can be done by using an 'equivalent stiffess' calculation and equating the laminate to a 'known' blade. some difficulty with this is that most blades aren't flat, so stiffness becomes a function of geometry as well as laminate thickness.
best way would be to make the bottom mould off an existing blade and scale the stiffness of the materials for thickness and lay-up accordingly (try it, learn and adjust).
Not too hard if you already have the materials but defo easier to just buy!
No doubt there's plenty of other ways to do it too...