I’ve used candles in all of the few solitary ritual ceremonies I’ve done.
In every case I have used a combination of white and beige candles as I wanted to keep my intent clean/pure. Since I was not holding circle with any intent on money, health, love, change, etc., I purposely did not include colored candles.
I’ve used a combination of tapers and pillars. I preferred the idea of small tapers because I have been able to exhaust them within just hours of lighting them. I found that pillars, which generally last longer over multiple days, left me wondering if my intents from prior rituals might still be lingering and possibly interfering with my next ritual. I didn’t have that concern with my other tools which I cleansed after ritual but those tools were made from more solid mundane materials like glass, metal, crystal, or shell. For some reason my mind perceived that the wax of the unused candles might retain my prior intents.
Any hoot, I have used colored candles within public circles. I’ve never led a public circle - just attended. But I’ve contributed color correlated candles to several ritual alters in support of the published circle celebration.