go for the condensor, the problem you had with backfire and missing is an indication of a faulty condensor, how far had you travelled before the misfire, about 3mile at a guess, plus you say you have a weak spark,
not sure wot price they are but for the sake of say £10 to£15 i would buy points,condensor, and rotor arm as spares you might not use them but you might just break down in the midle of no where.
