For a natural wood look, use either Loba Invisble or Bona Natural seal and Bona Naturale . If, you want a shiny finish add Loba Supra AT over Invisible and Traffic HD over Natural seal.

Have they let that flooring acclimate or is it just being unloaded and installed? Have they checked the moisture reading of the floor? Of the subfloor? Is that going over a cement slab?

Use water-based polyurethane instead of oil-based. It stays clear and does not give the amber look you're trying to avoid. Bona Traffic HD is a trusted (somewhat pricey) brand but there are others (just make sure it comes from a flooring specialist and not your local big box store). Make sure you're working with a contractor who's used water-based products before-- they don't go down the same way as oil. It sounds like from your previous post the guy you're working with prefers oil, and that's probably because that's all he uses-- the building trades are slow to change, and water-based products are relatively new (they've been around about 20 years, and are continuing to improve).