I am also seeing if i can get myself access to Hauberk of Sublime Lightness from HoH:S ... if I can get the lab total, might I be able to gain access to a lab text for this?
As to age, I thought I would start my character a little older ... he does have Strong Faerie Blood, which means he doesn't start aging until 50. If this feels overpowered, I can certainly start with a lower gauntlet age.
On the Ars Magica forum, most people use wards that give a bonus against attacks made with metal or wood, which is quite elegant. But again these are spells for after the gauntlet.
I've never come across the major fairie blood pre apprenticeship exploit (and I've known ArM5 for very long). So even if it gives you quite an advantage, use it (let your conscience be your limit). 100xp more or less won't be game-breaking.