Your potting mix sound like it should work well.
Watermarkings are a natural feature of some sempervivum, and are loved by many collectors. Some may have them year round, but most have them for a short season, usually starting in the spring and going through the summer. This trait can very depending on the cultivar.
When we receive plants with no names it is almost impossible to identify which semp it might be. There are thousands of named cultivars.
But that sure doesn't keep us from loving our NOIDs (No ID). Many of us have our collections of NOID sempervivum.
Please keep us updated with photos as your wonderful sempervivum settles in and takes off growing.
Come join us over in the Sempervivum Forum. We love having new members to share their photos and there new found love of hardy succulents.
http://garden.org/forums/view/...