Warning: every point counts.
I think I may have missed some variations, comments are welcomed!
(;AB[qc]AB[pc]AB[pd]AB[qd]AB[qf]AB[qg]AB[qh]AB[ri]AW[rj]AW[qj]AW[pj]AW[rk]AW[pi]AW[ph]AW[pg]AW[pf]AW[pe]AW[oe]AW[od]AW[oc]AW[mc]AW[kb]AW[lc]AW[kc]AW[rl]AW[sl]C[White will win any ko. What is the best endgame? Sente is not important.]AP[goproblems]
(;W[qe];B[re]
(;W[rf]
(;B[rd]C[CHOICE]
(;W[si]
(;B[rg]C[CHOICE]
(;W[pb];B[qb];W[oa];B[qa]
(;W[sg];B[sf];W[sh];B[rh]C[CHOICE];W[sj];B[pa];W[ob]C[The best result for both.RIGHT])
(;W[pa];B[sh];W[sj];B[qi]C[])
(;W[sh];B[pa]
(;W[ob];B[rh];W[sg];B[sf];W[sj]C[RIGHT])
(;W[sg];B[sf];W[ob];B[rh];W[sj]C[RIGHT])))
(;W[sh];B[ob]))
(;B[sh];W[sg];B[sj];W[qi]C[RIGHT]))
(;W[pb];B[qb]
(;W[oa]
(;B[rg];W[qa];B[rb]
(;W[si];B[sh];W[sj];B[qi];W[ra];B[sb]C[RIGHT])
(;W[ra];B[sj];W[sb];B[sc];W[qi];B[sf]C[RIGHT]))
(;B[qa]C[CHOICE]
(;W[si];B[rg]
(;W[sg];B[sf];W[sh];B[rh]C[CHOICE];W[sj];B[pa];W[ob]C[The best result for both.RIGHT])
(;W[pa];B[sh];W[sj];B[qi]C[])
(;W[sh];B[pa]
(;W[ob];B[rh];W[sg];B[sf];W[sj]C[RIGHT])
(;W[sg];B[sf];W[ob];B[rh])))
(;W[qi];B[rh];W[si];B[sf];W[sh];B[rg])))
(;W[si];B[rg];W[oa];B[qa]
(;W[sg];B[sf];W[sh];B[rh]C[CHOICE];W[sj];B[pa];W[ob]C[The best result for both.RIGHT])
(;W[pa];B[sh];W[sj];B[qi]C[])
(;W[sh];B[pa]
(;W[ob];B[rh];W[sg];B[sf];W[sj]C[RIGHT])
(;W[sg];B[sf];W[ob];B[rh])))
(;W[qi];B[rg];W[oa];B[qa];W[si];B[rh];W[sh];B[sf];W[pa]C[The best for both.RIGHT])
(;W[ob];B[rg];W[si];B[sh];W[sj];B[qi];W[qa];B[ra];W[pa];B[rb]C[Now optimal.]))
(;W[qi]
(;B[rh]
(;W[si];B[sf];W[sh];B[rg];W[pb];B[qb]
(;W[pa];B[qa];W[ob]C[RIGHT])
(;W[oa];B[qa];W[pa]C[Best for both.RIGHT]))
(;W[pb];B[qb]
(;W[oa];B[qa];W[si];B[sf];W[sh];B[rg];W[pa]C[Best for both.RIGHT])
(;W[si];B[sf]
(;W[oa];B[qa];W[sh];B[rg])
(;W[sh];B[rg]
(;W[pa];B[qa];W[ob]C[RIGHT])
(;W[oa];B[qa];W[pa]C[Best for both.RIGHT])))))
(;B[rg]C[CHOICE]
(;W[si];B[ob];W[nb];B[oa];W[sg];B[sf];W[rh];B[rf];W[na];B[pb])
(;W[pb];B[qb];W[oa];B[qa];W[si];B[rh];W[sh];B[sf];W[pa]C[The best for both.RIGHT])
(;W[ob];B[pb];W[si];B[rh];W[sh];B[sf];W[pa];B[qa];W[oa]))))
(;B[rg];W[rd];B[sf];W[rc];B[rb];W[qb];B[pb];W[ra]C[Black is in ko trouble.RIGHT])
(;B[rc];W[se];B[rd];W[sg]C[Black is in ko trouble.RIGHT]))
(;W[pb];B[qb];W[rf];B[rg];W[ob];B[qa])
(;W[qi];B[ob])
(;W[rd];B[rc];W[rf];B[sd]
(;W[qi];B[rg]
(;W[pb];B[qb];W[oa];B[si];W[sj];B[sf];W[qa];B[ra])
(;W[si];B[ob];W[sg];B[sf];W[rh];B[rf];W[nb];B[oa];W[na];B[pb]))
(;W[pb];B[qb];W[oa];B[si];W[qi];B[rg];W[sj];B[sf];W[qa];B[ra])))
(;W[pb];B[qb]
(;W[oa];B[rc];W[qe];B[re];W[si];B[sh];W[sj];B[rh];W[qa];B[ra];W[pa]C[])
(;W[qe];B[re];W[rf];B[rg];W[ob];B[qa]))
(;W[si];B[ob];W[nb];B[oa]
(;W[re];B[qe];W[sg];B[rf];W[sf];B[rd];W[se];B[sd];W[sh];B[qb])
(;W[sg];B[re])
(;W[rh];B[sg];W[qe];B[re];W[rg];B[rf];W[qi];B[rc])))