Of the 37 holdouts (in grf6-ho.txt):

2 & 3 have C(P¹(1), ...), so simplify.

Entries 4-9 are of the form M(C(C(S, ...), so don't terminate.

10-18 have M⁰(C¹(P³(1), S¹, ...), so the output of S is routed 
        into M, ensuring nontermination.

19-27 have M⁰(C¹(P³(2), _, S¹, _)), which does the same thing.

28-36 have M⁰(C¹(P³(3), _, _, S¹)), the third way to do it.

That leaves only two entries:
1x      M⁰(R¹(C⁰(S¹, Z⁰), P²(2)))
37x     C⁰(M¹(R²(S¹, P³(2))), Z⁰)

For 1x, see that C⁰(S¹, Z⁰)=1, and P²(2) as the iteration fcn in 'R'
    points to the prior value, so R¹(C⁰(S¹, Z⁰), P²(2)) is
    equivalent to N¹(1). 
But M(N¹(1)) doesn't terminate, so neither does 1x.

For 37x, note that R²(S¹, P³(2)) is λa, b: b+1, which can never get
evaluated to a 0, so calling M on it gives λa: ⊥.

That's all of the hold-outs, and turns out none of them were champions!