All white, playing 4 suit transfers

Uncontested auction: 1N-2C-2H-2S-3S-4H-P

1N opener held:

K842 QJ62 KQJ AT

Responder held:

QJT9 T94 9 KQ986

Is there a sensible route to 3N?  While neither 4 Hearts nor 4 Spades make, given a choice I think you'd prefer to be in 4 Spades.  Whose fault and by how much?

I guess if you play splinters you might sensibly get to 3N.

Does responder's auction show 4 spades, invitational values and 3 hearts (catering perhaps to AKx AKJxx xxx Jx)?  Or should he just bid 4 Spades to not risk a mixup?

Does opener have any reason to pass 4 hearts?