Tried all sorts of groundsheet. It was always just drop sheet plastic but in Phil's shelter one of the heavier cuben fibre materials is common. The last couple of solo trips I have been using a tent (of sorts), its in the MYOG forum with a cuben floor.
If not a 'packaged' tent then there are all sorts of options. I like the sewn in floor in Phils Golite shangri-la 3 (for example), simple (and the fly can't blow completely away .. if that was ever a chance).
Tried a few bivys, some (eg Outdoor Research) allow a mat inside but the lighter (waterproof) ones are usually too small. Just groundsheet, mat and bivy on top. last time I used a Klymit mat (that does fit inside the bivy), gets even further into personal preference and experiences then though.
tbh I didn't like the Akto size and style tent and similar options, otherwise (if I could live with it) I would have just kept Luvy's/Tortoises Akto

The tipi/Cuben mids just give more room for less weight (something I thought might help). If I had a chance to jump into the Nallo in a blizzard that would be the choice but then that is a lot of weight to carry everywhere for want of a bit of extra care and campsite choice.