For me:
Offal is "oh-full", awful is "awe-full".
Golf is "Gawlf".
Opera is "ah-perr-uh" (ah-purr-uh?).
Octopus is "ahk-toe-puss", or "ahk-tuh-puss" if I'm very tired.
Octavian would be "ahk-tave-ian".
Don't ask me to use IPA, the vowel system in that thing is a wretched mess missing half the vowel sounds I actually use (evidently they're "between sounds" / diphthongs, so use double-symbols... which seems very arbitrary given some of the sounds that they do give distinct symbols to... and every audio guide to IPA makes all the vowels sound like a stereotypical French guy from a Money Python sketch choking on a mouth full of marbles while trying to pronounce the sounds).