How much should i charge on my secured credit card to get the best credit rating?

I can charge up to $500 on my secured credit card and want to know how much should I charge on my secured credit card to get the best credit rating. I need to build credit because I got none.
I’ll be paying it off every month.

I’m wondering how much I should charge on my secured credit card every month out of my $500 maximum.

I’m comparing two credit card reward programs. Card #1 offers 5% rewards on supermarket shopping for about 6 months, and 1.5% on all other purchases. For the other 6 months, the rates are 1% on supermarket and .5% on other purchases.

Card #2 offers 2% all year on supermarket purchases and 1% on everything else.

I realize it depends on what I charge on the card, but overall, which program is better?