USWE waist packs 6L vs 2L (Zulo2 vs Zulo6)

Any chance anyone has both these bags? I got the 6L bag but it is too much bag for me… but I really need the 1.5L bladder. I contacted USWE and they said they don’t “recommend” the 1.5L bladder in the Zulo2 pack but I’m wondering if could work, just maybe not ideally. Thanks!