Loose ball bearings. Question about material and grades

Learning as I go along when it comes to maintenance. My beater wheel hubs need overhauling and the crappy weldtite bearings I put in the GF's BB feel rough when spinning the axle by hand. Been doing some research and now realise I need a much better grade of bearing than the weldtite grade 1000. Good thing I haven't finished building the bike so it hasn't been ridden like that!

Long story short internet consensus is simplybearings is the place to go. I can't find much info though on which material I should go for, 52100 hardened chrome steel or 440 hardened stainless steel. The stainless steel is marginally softer, which would mean it would wear sooner, but potentially wear on cups/cones would be less. But I may have that all wrong. Then the second question is the grade. They only do grade 100 or 10. Is it worth biting the bullet and going for g10? Or do I look for other sellers who do g25? (Can only find US sellers for that)

Thanks in advance for all advice!

Probably it doesn't matter.

Haha probably you are right! Anyway in case anyone digs this up with the same question cheapest and best option I found was on Amazon.com £12.70 including shipping for 500 g25 bearings, 100 each of 1/8, 5/32, 3/16, 7/32 and 1/4 sizes

I always use grade 10 chrome balls in hubs. They run smooth with these. Weldite balls should not be sold as they will ruin your hubs. Grade 10 bearings are not much expensive than grade 25 and are rounder. It what campagnolo use in there hubs ever wonder why they are so smooth and last so well. Chrome balls are harder than stainless balls which is a good thing. Stainless balls are also more prone to pitting than chrome steel. Chrome balls rust more easily if the grease runs thin so use a peristaltic grease.

All these are pointless if the hubs is pitted.

I always use grade 10 chrome balls in hubs

↑This. If you're just doing a few hubs, the price difference compared with lower grades is negligible. I tried the stainless balls in my RollerFort, but they exploded long before any corrosion resistance could be brought into play, so I'd avoid those in any bearing designed for Chromium Steel balls.

Thanks for the input guys. I'm going to have bearings galore by the end of this! I guess I'll find out the condition of the hubs/cones when I pull them apart.