Experimenting with common Nonpermanent -> Artifact Research ALT cards. Not sure this is actually doable, but why not try it?

The first face isn't really green, but I like how you can basically just hard cast the back face as a 2G mana rock

Would they still feel thematically connected if the first side tutored a land?

I'm afraid they would be too connected as land tutor, especially if the land is put into play. Both spells would put a permanent into play that taps for 1 mana. Unless you think there is enough lands/artifacts matter to make them feel different in a deck that would run this.

The front side is always two of the backside, too, which complicates matters.

Aether Fission, I would argue, is green. It doesn't accelerate, it only fixes. Red doesn't fix, it accelerates. While it isnt usual for green, it's far more in line with green than red.

At the very least, it's a bend I'm comfortable with.

Yeah, I think you're right

Why not simply have the front face be a Rampant Growth or Lay of the Land?

The theme is "two transient into one permanent". While that's not concrete or anything, it'd be nice to maintain the theme.

The doubling rather than the "transient into permanent" part was far more apparent to me. What about making it double Lay of the Land?

Yikes. The transient-into-permanent theme was very obvious to me, and getting land cards in any way is too permanent to maintain that theme IMO.

I'm not a big enough fan of this change to actually put it into the file yet, I think. Let's keep the Manamorphose effect for now, and see if we can't find a better green effect.