All these figures are confusing. I'm not on expert So I record FHD 1080/50.00p 50M,OK?

When to export: What shall I use? Pal 576 x 720 /50i??

Will that fix the black frames?

I have now a memory card  Extreme pro sdxc 64 GB Speed 95. Is that OK or Is a higher speed better?

Regards

Tommy