Well, it's been around an year since I first started wearing thongs. What started as a gift from my gf for spicing up night, turned out to be a such an eye opener to me that thongs are the most comfortable underwear for men.
After a number of trial and error attempts, I finally found a humble brand that's making some of the most comfortable thongs for men. These are exactly what I was looking for - spacious pounch (per my size), soft and moisture wicking fabric (Bamboo fiber), comfy back strap and not too funky. These are the ones that I am wearing daily since last 2 months.
I think these are actually unbranded thongs (similar to ikingsky). They are only available on Amazon.
For someone who loves wearing thongs primarily for comfort and as a daily wear, this brand (specially Bamboo fiber thongs) is the one to go for. Do try it out.