The fact of the matter is that Vegeta was weak enough to fight with Gohan (likely enraged power) for an extended period of time. He doesn't need to be above 40k as an Oozaru for this to make sense. Your point about Kaioken x5 doesn't contradict this either. Kaio states that Goku had no strength left after the Kaioken x4, so he was certainly far from his best when speculating about x5.
Can easily look like this:
Goku: 8,000
Kaioken x3: 24,000
KKx3+KHH: 24,000+
Exhausted: 4,000
Hypothetical KKx5: 20,000
Vegeta: 18,000+
Gyarikku Ho: 24,000+
Oozaru Vegeta: 40,000
Genki Dama: 50,000
So I'm not sure what you're arguing here. I said from the beginning that the Genki Dama could plausibly be =<2x the Gyarikku Ho, and it definitely can be depending on if you believe Goku's Kaioken KHH was amplified.
For example:
Kaioken x3 KHH: 27,000
Gyarikku Ho: 27,000
Oozaru Vegeta: 40,000
Genki Dama: 50,000
Where's the problem?