Tried this twice this year. 1500 mg * 2 days in July and 2000 mg * 2 days in December.
Both times varicose veins in my lags rapidly decreased, but not quite disappeared after taking these. Then reemerged over the next couple of weeks. Also I looked younger for about a week right after taking them.
Best guess the paper saying the kidneys regulate the amount of senescent cells is right. Remove senescent cells and the body just puts them right back. You would need to clear senescent cells out of the kidney for long term effect, which would be extremely difficult as the organ system functions to remove toxins. Apparently nature may have put the regulator for aging in some place where you cannot override it simply by eating some flavonoids.
I suspect senolytics only work when paired with robust senomorphics to slow down the rate at which senescent cells are replaced. Also I suspect flavonoid based approaches are going to have a problem with rapid resistance to the drugs/supplements.