I get multiples, but recent seasons have been screwed up, so I get multiples on loquats and others that are not supposed to repeat crop.
Good wampis will be 80% + seedless if grown in isolation. With cross pollination seedless ness goes down. I just harvested my yeem pay wampees and they are beyond delicious, like a candied lemon rind. They are angular and bright yellow skinned, unlike the other types, which are oval and bronze, like a guy sahm, which have more aromatic, spicy, grapefruit notes about them. The problem with this variety is that it's too small and gets stung by fruit fly, so will never be more than a curiosity here. The bronze ones fare better, but are nowhere near as sweet. I'd sow the seeds to try to get a bigger fruit from seedling, but they are seedless.