I also found the stock tips to be best, tried spinfits, sound about the same to me, except sticks out way more. It's true, deeper is not better, it'll just muffle the sound.
Nobody was able to tell what brand are those stock JH Audio silicone tips. Even JH don't know.. I'm really looking for the brand who makes them. Because I tried literally all silicone tips from Ortofon, Spinfit etc.. and those Layla/Angie stock are definitely with best fit and sound for my ears. This apply to other IEMs as well in my inventory.