Vis is detected as a infinite magnitude effect of any realm. That is all spells to detect magic effects will also detect vis of any realm. Spells to detect auras, regione or the Gift will not detect vis. RAW is a little ambiguous on this, so this is an interpretation.
Copying of ability summæ. The copyist needs to accumulate 3x level points to complete the copy, not 5x as RAW says. This is done to make the copying times for arts and abilities more comparable in terms of xp gain.