Help adjusting pattern

Hi, I would like to beging making a vest. The pattern calls for Plymouth Alpaca DK with a size 4 needle gauge 22 sts and 32 rows= 4" in st stitch. The yarn I would like to use is more of a sock weight (Plymouth Royal Llama Silk) 4.5 sts to 1" using a #8 needle. I could use some help trying to make the adjustments before I begin.
Thank you.

That would be an awfully loose knit to use sockweight on a size 8 needle, unless it’s a UK pattern and uses the old UK sizes which are the same as a US6/4mm. A size 4 US needle is a 3.5mm and a little small for a DK, so make sure you’re reading those needles correctly. I would just try it with the size 6/4mm and see what gauge you get. It would help if you can link to the pattern or information about it to make sure you’re reading the needle info correctly.