oh hai brad.
you'll find that carina blacktop loom is a bit different as to the body loom plugs than a levin/trueno/carib. TBH you can splice them together but i relied on a friend who is a genius to help me rewire it. you will be better off finding a silvertop loom then adding/modifying wires for map sensor instead of maf. it has been done before by a few guys on here there was a thread not long ago which was along the same lines as yours here where it was explained.
we did it the hard way by rewiring the fusebox, adding starter relay and 3-4 extra wires around the engine bay as well as the dash stuff to get everything working.
with a silvertop loom all the body loom plugs are in the same places so makes it much easier.
really depends how far you have got so far and if what you have been doing has been working. if not i'd say this would be worth a go. if you need pics/help with anything PM me and i'll see what i can muster from my limited wiring memories of what we actually did and why. LOL.