Yea by having massive ring sizes I think the anonymity set for Monero is already vastly larger than Zcash when it comes to receiver privacy because of one-time stealth addresses, but that isn't true for Monero senders (but you're right when it comes to t->t, z->t, t->z which is the vast majority of transactions ) All this debating will be pretty irrelevant though when FCMP comes to mainnet