Gyumao ought to win. We're forced to draw from the anime in terms of his feats, in which he casually tanked BoDB Goku's attacks. I don't see Giran tanking Galu's hits to the same degree, or being able to endure multiple rifle shots as Anime Gyumao did. I doubt Guruguru Gum would help much due to Gyumao's size, seeing as how Giran would've tried increasing the amount after Goku broke out if he were capable of spamming it in greater amounts.