The Delay action p127 states "This changes his Strike Rank to the number when he finally does act." so effectively we have a situation where two combatants have the same strike rank.
Under Calculating Initiative p125 it says "If two participants tie scores, then they act
simultaneously. If both are attacking simultaneously, a weapon being used to strike cannot also
be used to parry a simultaneous blow."
So if you Delay then your SR is changed to the SR on which you finally want to act (the same SR as the enemy) and both attack simultaneously but you can only parry with a shield or off-hand weapon.
Hope this helps.
Wow I need to do this against enemies that have only a two-handed weapon when I have a shield.
He can't parry, but I'll suffer no penalties, yes please.