I have always blocked on the following. I have folded a blanket just larger than the area I need. On this I have folded a cotton sheet. I pin the item on that.
I wash the item in a wool wash as a rule and then gently squeeze out the excess water. Don't wring it just squeeze. I wrap the item in a towel and then press again to try and rid more water. Lay item on the sheet and pull into shape and pin. Go back in 30 to 60min and check and re-adjust pins if necessary.
Sometimes I will unpin and change the sheet and then re-pin. It depends on a few different things.
Some yarns will not block that well. I don't know the qualities of the yarn you mention. Is it hand wash or machine wash?