Today's bearings are awesome. If you buy SKF, Timken, Torrington, your time would be better spent testing some other part of your bike: your bearings are going to be fine.
The Basic Dynamic Load Ratings, Static Load Ratings, and Thrust Load Ratings are published and accurate.
What matters in your case is SEAL DRAG!!
Bearings are sealed obviously to keep out moisture and debris. The seals will impede the rotation of your bearings, BUT it's no big deal because you can just remove the seals and there is no more problem.
Most of the time you can purchase bearings: sealed, unsealed, steel-shielded, or with one of the above on one side only.
Summary: Buy a quality bearing without seals and your all set.