Kobo Glo with 2.8.1 here.
Does the font patch work for you? I tried the advanced font options for some fonts I sideloaded and it only works when the book is a kepub, otherwise I can see the changes into the preview window, but nothing happens to the actual text.
Anyway, apart for this, I think with this patch I reached my Kobo Nirvana
Perfect size, perfect line height, perfect font weight.
