The question that needs a precise answer is this: Did He or didn't He? Did Christ actually make a substitutionary sacrifice for sins or didn't He? If He did, then it was not for all the world, for then all the world would be saved. (Palmer, The Five Points of Calvinism, p. 47.)
When Palmer admitted that predestination, as it applies to the salvation or eternal damnation of every person, is illogical and not consistent with a loving and just God, and offered no justification for that view other than he believes it anyway; I rejected his brand of Calvinism.
The rest of his book seems solid, at least as far as I've read, so I see no reason to reject his whole book just because he admits he doesn't understand predestination.
I'd be curious to see the citation in question, where Palmer "admitted that predestination, as it applies to the salvation or eternal damnation of every person, is illogical and not consistent with a loving and just God".
I'm not doubting you've a specific excerpt in mind, I'm just wondering whether or not the wording in question admits of other interpretations than that which you have derived. Perhaps Palmer did not intend the meaning which you have gleaned from that particular section, or constructed his wording poorly.
At any event, I'd be interested to read the Citation you have in mind. Thanks!
best, op