White (heavily spined of fluffy) Cacti that don't need full sun

[Grimm]

I was wondering if anyone has any suggestions for white (heavily spined of fluffy) cacti that don't need full sun. I know most/all Mammillaria with dense fluff or spines need full sun or they either don't grow dense spines/fluff and/or they etiolate.
All three of the windowsills that I grow cacti on face SSE, but two have net curtains between the cacti and the glass so I assume aren't suitable for cacti that need full sun, and I've run out of space on my full sun windowsill.

So far I have a Notocactus scopa, Rebutia albiflora, Rebutia hoffmannii and a heavily spined Gymnocalycium bruchii that should be okay on my shaded windowsills (from what I have read, happy to be corrected), but little else.

Thanks

[jfabiao]

I have no idea how well do these adapt to lower light conditions, but you have a few columnars that are white (Cleistocactus straussi, Espostoa melanostele, Espostoopsis dybowskii, Cephalocereus senilis...). Parodia haselbergii is commonly found in white spined form. There are also some Haworthia and Gasteria that are heavily white spotted and actually prefer more shaded environments.

[greenknight]

Parodia rudibuenekeri, as well.