Hoya UV 0 HMC vs. SHMC
Well, the strange thing for most ppl is you will ask for more if you don't have the best.
If Hoya produce SHMC, they must have a reason, maybe for marketing (sales, or profit margin).
If you would like the best quality, just shoot without filters.
For me, I have 13 lenses with different brands of filters, including Hoya. I don't really find major differences between them. But, sometimes, you may tell yourself that, with the same picture, using a different filters maybe better......
So, my recent choice of filters is Heliopan SH-PMC UV.
But, I think, just buy any reputable brand with multicoating. Like Hoya, Nikon, B+W, Heliopan and etc.... is okay, without large differences (for UV).
But personally, I will go for B+W or Heliopan, since they are brass mount. To me, to buy anything, I need a reason, that is, they are both multicoat (for multicoat version, of course), and they are brass mount, makes it easier to remove the filter from the lenses.
My answer may not help you, but it's just my feeling about filters.