I'd say Ronnie's arms are somewhere around the 21'' mark, 22'' might be a possibility... but these figures of 24 and 25 inches are just ridiculous.
Greg Valentino's arms stretch the tape to 24.5 inches (he had them taped on Ripley's Believe It Or Not), Manfred Hoeberl at 6'5'' and 300 lbs had 25'' arms, and they looked horrifically disproportionate.
If Ronnie's arms were really 23 plus inches then the height of his arm from the peak of his flexed biceps to the belly of his tricep would be supstantially taller than his head. It's not! Ronnie's only 5'10''/5'11'', a 24'' arm would be about 10 or 11 inches tall... couldn't that be measured relative to Ronnie's height in a photo??
I'd go so far as to say Ronnie's arms might well be somewhere between 20.75 and 21.5 inches in competition shape. Any bigger than that and his arms would be sherical because the distance from Ronnie's deltoid tie-in to his forearm is only about 12 inches (if that).
Don't believe the hype!!
The Luke