Ratio for thinning polyurethane?

[Kev Godwin]

Next week I plan on starting to finish the oak top of my new conference room table. It has been several years since I have thinned poly-u to help the application flow and reduce streaks. I think I may have used about 5% mineral spirits in the past. Can anyone offer me any advice on a recommended ratio? Thx.
Kev

[Steve Schoene]

You will likely need a bit more thinner now since VOC regulations have caused varnish makers to increase the percentage of solids. It is not at all critical, the only harm of thinning to much is you might need more coats. Try 10% and see it that works for you, then adjust.

[Howard Acheson]

I thin the first coat 25-30% with mineral spirits. Subsequent coats are thinned 10%.