He was on rachel ray maybe 15 or so years ago and she measured his arms at 20” and around that time I believe he said he was 265. I’m gonna say the hulksters arms were 21-21.5” at biggest. I read an arrival about the movie no holds barred and tiny lister said they picked him cause they needed someone a little bigger than hulk and tiny said he was 6’6 305 with 21” arms for this movie and you could see he was a little taller and bigger and his arms were a little bigger or same size. So hulk was prob 6’5 at his peak height.
When the WWF was having its big steroid trial in the 90's, one of the prosecutors really pressed him on the size of his arms, and the biggest he claimed was 22". Later a tv report chased him around trying to measure them.
There's a good book on that era called Sex, Lies and Headlocks. Vince had a guy who's job it was just to make him tuna fish all day, they sad you knew when Vince was in the building because the whole place would stink of fish.
Hogan claimed that SS Billy Graham introduced him to steroids by giving him Winstrol and Dianabol. Graham would get Hulk back later by telling reporters that Hulk's ass was so scar tissued up that Graham had to hunt all around his cheeks to help Hulk inject 3cc's of test a week.
The book is filled with that type of stuff.