Fomori Metavariant of the Troll Metatype.
I'm big. But not so lumpy. And my ancestry is from Scottland, thusly the "British Isles" Where the Fomori meta-variant is from. I don't feel all that magical but at only 4% more magic users in the meta-variant that still leaves room for tons and tons of non magi Fomori. I'd probably end up a Fomori Rigger or Street Sam.
Trolls are pretty rare. So Metavariants of Rare metatypes are even more so.
Failing the Fomori, I'd fall soundly into the Orc Metatype. Baseline Orc or maybe Ogre.