There's actually no need to determine when you spread your field how much of your AT field is used for neutralization, and how much of your AT field is used for deflection.<br/><br/>The strength of your AT field is automatically added to the breach bonus of your weapon; However, if you want to allow others to beneift from your AT field strength to damage an Angel, then you'll have to spend a half action within 20 dam of the angel neutralizing its AT field.  When neutralizing an Angel's AT field, you can spend any amount of AT strength you have, but generally you'll want to spend your entire available pool of AT strength, unless you expect to be hit by attacks from something with an extremely weak AT field.<br/><br/>The angel itself has an AT strength of at least 9, so you know that all of its attacks will have that minimum breach rating, so deflecting the angel's attacks is most likely impossible!