So im going to start this discussion again as the colony wide benefits are on the cusp of becoming a reality.
And im going to say that only the B method kind of makes sense because the early multicellular is supposed to be about placing cells while the later stages would be about placing tissues already, so, i feel method A is reducible to method B.
Also about the photosynthesis problem, we could just program the cells which have that organelle to be sensitive to surface covering (how many cells are connected to it).
Theres also something else of which i thought about in multicellular that might be affected by surface area which is heat dissipation and metabolism. I heard somewhere that the cells of larger animals have a slower metabolic rate otherwise they would explode because cell number scales with the cube while the surface area scales with the square of the size. So, heat and metabolism could also be something that can be considered with multicellular organisms, but they still could be treated as a property of the whole organism not the single cell of that organism.