I don't know how responsive the Garbo A & E are, but I don't know if I would replace them with Obligatos. I'm using a full set of Oblis right now and am also looking to replace the flabby lower strings. I've decided to try a rope core, Thomastik Superflexibles specifically, for the A & E and stick with the warm, punchy Obligatos for the G & D.
Hope you find the sound you're after. Grenadier is a great player.
Hope you find the sound you're after. Grenadier is a great player.