Best surface for pricking leather?

Dear all,

I was making a photo holder for my bestfriend, when (to my horror) I realized I was pricking really crooked stitches.

Since I misplaced my awl, I thought to prick all the way through 2 layers of leather. The front pricks looked fine but when i turned the piece around the pricking was really crooked (see photos).

In an attempt to get straighter stitches, I found that when I pricked on different tables, it was easier or harder to prick STRAIGHT through the leather. Is this possible? Is there an IDEAL working table material? I'm using a Japanese Pricking block so I think the table is making the difference.

Any tips on preventing snaking stitches?

Thanks in advance ☺