Transfers, 2/1

Finally I figured it out! It's a structure I had already made once for 1NT. Retransfers to give you all the possible room.
1S - 2D, transfer showing hearts. I wanted to fit in weak hands with long hearts that just want to play there, single suited and two suited invitational hands. Of course it has to be able to handle them all when GF. In addition I want to be able to show some 6+H, 3S hands that wouldn't want to relay. (For the fear of competition and to get the chance to show choice of games) I know some aim for being able to stop at 2H here with inv opposite minimum opener without much of a fit, but I think that's aiming for rather small target. I'd rather have a way to drop off in 2H with weak hands with hearts.

1S - 2D
->
2H = Nothing special, should happen some 80% of time I guess.
2S = Good long spades with short hearts, doesn't deny or promise extras
My 1S is limited, so everything else shows a fit. You need something to show strong hands in natural so you have less ways to show hearts but that's not much of a problem since I feel I have too much room.
2NT = Heart fit with bad spades and good minor suit cards, suggesting that spade shortness isn't a bad thing.
3C/3D = Shortness
3H = Other max hands with hearts
3S = Some wild shape like 64 or 73 majors with good spades. Not forcing but opposite some KQ of hearts, should definitely be in game.
3NT = This is the one hand that doesn't have fit, it's a gamble with solid 7+ spades and a minor card, usually heart shortness.
4C/D = Void with some freak
4H = 6511 or 7411 I guess...

Now, where the beauty starts.
1S - 2D - 2H
->
2S = Transfer to clubs, inv+ (54+)
2NT = Transfer to diamonds, inv+ (54+)
3C = Transfer to hearts, inv+ (6+, may have 3S)
3D = GF with 6+H, 4D
3H = GF with 6+H, 4C
3S = GF with 6+H, no shortness
3NT = Solid hearts (AKQJxx or AKQ 7th)
4x = 7+ hearts and a void (I use steps but could be natural as well)

Over those transfers, bid the next step with non fitting minimum, show the fit at the minimum lvl with min. Next free bid denies fit and is max, one after that shows heart fit and then you show diamond fit and shortness in steps.
So:
1S - 2D - 2H - 2S
->
2NT = Min, no fit
3C =  Min, at least xxxx in support of clubs
3D = Max, no fit
3H = Min, heart fit
3S = Max, heart fit
3NT = Max, at least xxxx support to clubs, no shortness
4C =  Max, at least xxxx support to clubs, heart shortness
4D = Max, at least xxxx support to clubs, diamond shortness
Over 2NT 3C shows 55 and is NF, 3H shows 64 and is NF. Others are patterning out with GF hand.
Note that over 1S - 2D - 2H - 2NT - 3C, you are bit jammed (Can't get back to 2NT) My suggestion is actually to just show the 1543 as balanced invitation, whatever your way to show that hand. That's how I handle 2533 anyways. Of course you can also just let it die at 2H and hope you didn't miss anything. (No great heart fit opposite, but you may end up in 5-1 fit)

Over 1S - 2D - 2H - 3C
->
3D = Min, suggests spades instead of hearts
3H = Min, typically at least doubleton support
3S = GF with no real heart support
Others fit hearts and show shortness in steps.

That's about it. I think you can easily fill in the blanks. I guess I should go around testing this.