General observations:
There's nothing wildly original about any part of the system, but it's put together with a few salient characteristics of the Fantunes 1N in mind, so hoped it would interest other Fantunes players:
1) that opener has a wide enough set of hand shapes to make asking bids relatively better than shape-showing bids by opener (this is why we ditched our original Keri system)
2) that unusually in our version, opener can have either 5-4 or 2-2 in the majors (this was originally a big worry for me, but I spent several hours testing out deals on BBO and didn't find any where it seemed to do any harm at IMP scoring)
3) that (as with weak NT in general), game-hunting is more important than slam hunting, hence several NF bids after a Stayman response
4) if in doubt about which options are most useful, I've tried to keep it simple
5) that we largely ignore the possibility of P having a singleton in our suit. Also couldn't fit the single-suited minor invites of our Keri system, and some of the rightsiding. Can't have everything
Anyway, onto a more detailed summary of the bids:
2♣ = regular Stayman, though with 5-4 in the majors, opener should bid his longest first, since this will be Garbage Stayman relatively often
2♦♥ = regular Xfers. Slam-seeking single-suiters will only go via these if they can splinter afterwards. With 5-5 in the majors gf and no slam interest, you bid 2♦
2♠ = range finder, inv (with no 4cM) or slam interest
2NT = GF 5 card Stayman (details completely ripped off from MickyB other than the 3♦ response* and major inversions, though I think he took it from Meckwell?)
3♣♦♥ = nat, slam try (with no shortage if in ♥s)
3♠ = GF with 5-5 in the minors
3N, 4♣♦♥♠ all to play (ie preemptive for minors)
After 2♣ 2♦:
2N invites
3♣ to play
3♦ doesn't exist atm
3♥ NF inv with 5-5 in the majors
3♠ single suited game try (no shortage)
After 2♣ and a 2M response, 3m is to play, the cheapest oM bid is a slam try in ♠s, others are what you'd expect.
After xfers most bids are standard meaning, except after 2♦2♥/ 2♠ is nat inv+, then:
3m is an accept with a ♥/♠ fit
Then responder's 3♠ is 5-5 gf, allowing you to stay below 3N when opener has 22.
After 2♠ (range-finder):
3♣ is max no 5cM
3♦ is max with 5♥s
3♥ is max with 5♠s
After 2N (5 card Stayman):
3♦ shows (54)22
3♥ shows 5♠s
3♠ shows 5♥s
After higher responses, bidding is natural.
Finally, after 2N 3♣, 3♦ forces 3♥, after which responder bids 3♠/3N to show 31(45)/13(45)
* This was non-existent for MickyB last I heard, but nicely filled a gap for us that he doesn't have