eccokie,
if he is drinking fine, then no nid to introduce, but its really up to you. But starting solids really requires some commitment, so have to pick out a fixed timing and feed daily to let baby have an idea, but of coz starting out, juz feed for fun on and off is more ideal IMO.
It is really fun to feed, make sure you get hb to stand by the camera!
I think have to discard within a mth from opening. The box shld have instructions. Im not sure abt heinz, coz I already threw away my box. =p