Yfwd s1kl psso

On the purl row after I have psso on purl do you purl the yfwd stitch or do you purl into back if I just purl it leaves a much bigger hole than

if I purl into back of loop
Trying to create a diamond effect

You can do either. Purling the yarn over will leave a larger eyelet than purling through the back. It’s your choice.
The diamond stitch pattern is lovely.