Just Forget About Me.
Pe Me 10
R: Personal D:Mom T:Room
The mage, when in a group, casts this spell on herself, at which point all members in the group, and those observing the group, forget the Mage is present. The spell is broken when the mage draws attention to herself (i.e., by speaking, knocking over a jug of milk, or hitting somebody etc), at which point those who were made conscious of the event, notice the Maga. However, even when the spell is over, no-one will realize that the spell had been in effect without magical or supernatural assistance, rather they will assume it was just a natural oversight. Should by chance, someone with supernatural power (such as a magical dog, or a hedge wizard with second sight, etc), draw attention to the Maga, then again the spell will be broken by those noticing the event, but again no-one will suspect that magic was involved. I designed this spell for a female Jerbiton court wizard, who used it to over hear indiscretions among the nobility, hence the female gender usage. Her sigal was a very faint ‘Ssshhh†sound, which was far too subtle for most others to determine what it was.
From page 111 Personal:
The spell only affects the casting magus
or things that he is carrying or wearing.
The [color=darkblue]Target is thus never larger than individual.
Those better versed in the Magic system will likely be able to help out with suggestions.
If you are not in fact destroying the Memory ,
the description seems more like Rego effect.
If the Maga were well known at Court ,
a base level 10 PeMe (page 150) is probably needed.
The level 03 or 04 effects seem a bit too low for what you are attempting.
The range should be Touch, and then it will affect anyone in the Room, NOT everyone that might be seeing the character. For that you would need Range Sight, and Target Group (with perhaps some Size magnitude increases).
The duration should also be extended, as a Momentary effect could erase the target from memory but not prevent newer memories from forming after that. The duration is comparable to at least Ring, with a +1 for being nonstandard.
The PeMe combination has the advantage of the change being "natural", it cannot be later detected by magic (although a careful examination could reveal something is missing from the memory). I am not sure if a Rego effect will be appropriate at all, but I don't have the books with me.
I believe, from my interpretation of the rules, that using PeMe to hide oneself would only work in past-tense. The people would be aware of the person and able to interact, but then could immediately forget that they had done so, even from something as small as turning to call the guards, and instantly forgetting why they'd done so.
Of course, PeMe only effects memories created by the time the spell is cast, I believe Re or a Vi requisite (thus a definite +1 to the Magnitude) would be required to make it a continuous process. I do agree with keith that this would start at a higher base than 3 or 4. Seems more like a 10 to induce this type of short term memory loss (a word might be considered a detail, as in Tip of the Tongue, but a person walking in your midst is a more durable thought I believe).