1950's vintage old (and in bad shape) red oak has been sanded and "it is what it is". Where there had been a fire and other damage like buckling (probably from water) we had to buy and install new red oak. The contrast between them post-sanding is very visible, especially in front room which is the entry point of the house.

We're thinking of staining all the hardwood flooring with a dark color, like MiniWax's "Early American". We have lots of windows so a dark color won't be that terrible...but of course we'd choose to go lighter if we didn't still have some dark splotchy spots here and there.

So...my question is: Should I use an oil-based stain or can I go with water-based? Which has best penetration and is most long-lasting and least likely to fade with sunlight from all those windows? Then...if I use oil-based stain, do I have to necessarily go with oil-based polyurethane? Or can water-based poly go over an oil-based stain?

Btw I researched Bona products but they're not carried here, and they cost so much...plus they'd have to be shipped here. I hate the smell of oil-based anything, and I also have a mild case of COPD so prefer to protect my lungs. So that's why I prefer to use water-based products...but I don't want to have to do this over and over...I want hdwd floor coatings that will have the best longevity.

Thanks for your advice!