Roger sharing lead vox on Sheer Heart Attack and Father To Son

So if I remember correctly, Roger shares lead vocals with Freddie on both Sheer Heart Attack and Father To Son. I'm having some trouble actually figuring out what parts he sings though. I kind of figure that the 'you won't understand a word that's in it' section of FTS is Roger singing, though it does kind of sound like Freddie at certain points as well, which is probably why I'm confused. Same goes for Sheer Heart Attack, where I've been told the second verse is Roger. Any chance of confirmation?

For years I've never fully understood who is singing what on the studio track "Sheer Heart Attack" from "News Of The World".

i pretty sure i hear Roger in the "joyful the sound....chorus"
and the "kings will be crowned..."
and sounds like him in the backing on "you won't undertsand a word that's in it"
and coming out of the bridge..."sing if you will"
the final "father to father to father to son2
not necessairly on lead - but in there
and on lead the final refrains of "joyful the sound" repeated - that sounds more Rog lead than Freddie

on SHA
the "hey-hey-hey the DNA" etc and "do you now do you know"
the choruses,

second verse is Rog

some of the phasing make sit confusing, but focussing on one bit of a passage, identifying the voice and following it helps

Roger doesn't sing the 'write it all again before you die' in Father to Son though he does say the 'yeah yeah' part after it

Father to Son: It's all Freddie (including 'yeah yeah', etc.) up until the pyramid effect ('father to father to father to son', which, technically, is sung by the backing vocalists, most of whom are also Freddie). 'You don't understand a word that's in it' is Freddie + Freddie. The whole coda ('joyful the sound...', etc.) is sung by two Roger's, chiefly in octaves (as he'd do later on in Drowse).

Sheer Heart Attack: It's a mixture. AFAIR, it's Freddie in the verses, double-tracked. Roger sings some bits in the lift (e.g. 'ticulate') and of course he does all of the backing vocals as well.

I kind of like trying to pick out who is Freddie and who is Roger, and sometimes even Brian, in the backing vocals of older Queen records. I just really love how distinct their voices were, and how they were very good for different things.