If 100grm of squash has 100% RDI of carotene, how much roughly could be eaten daily without skin yellowing? Would mineral oil stop absorption much?

All you want. 1st, there is no official RDI for carotene; everybody has a different number. 2nd, I've never seen carotenosis from squash (and my daughter, a vegetarian, eats a TON of it). 3rd, carotenosis due to eating vegetables is harmless, so if you somehow eat enough squash to yellow your skin, cutting back will reverse it. So eat what you want. Mineral oil would have no significant effect on absorption.
Think Variety . How much squash do you plan to eat? Think in terms of lots of colors when planning vegetables for your meals. Variety is the spice of life - and health. Mineral oil, though, is not part of a healthy eating plan. .