Men's Cardigan in DK weight alpaca yarn

Good Morning!

Let me begin by stating that I have done some knitting following specific patterns with great success.

I’m knitting a Cardigan for my wonderful husband and am winging it without a formal pattern (I may live to regret this decision, but I do love to live life dangerously). Also, I couldn’t find a pattern he liked that used DK weight. I have done extensive tailoring and sewing so some of my skills sets will transfer, I hope.
I’m using DK weight Alpaca yarn and based on his chest measurement of 41 inches I casted on 117 stitches for the Back on size 6 needles to knit the 2 inch high ribbing (K1, P1). I’m planning on knitting the body of the cardigan on size 8 needles in a very simple check pattern of Odd Rows 9 K, 9 P across, and Even Rows 9 P, 9 K across. I’ll figure out how many rows to continue this pattern based on the width this gives me. I’m trying for an alternating square checkered pattern in knit stitch and purl stitch.

My question to the more experienced knitters is, based on all this, have I casted on enough stitches? If I’ve casted on the wrong amount, what should I cast on?

I’m also thinking ahead to the sleeves and would like any opinions.
Should I knit the sleeves in the same pattern as the body (checks) or could I knit the sleeves in say a “seed” pattern (K 1, P 1 across, P 1, K 1 across).

Thank you for sharing this wonderful hobby.

It’s simple to figure out how many sts you need. Take your sts/inch times the finished measurement and that gives you sts you need. That would be with the larger needles and in the pattern you plan to use for the body.

My advice is for the sleeves:
with a pattern as repepetive as chess board, do not do the sleeves in pattern at all. Just do a bit of ribbing and then stochinette stitch all the way up.
I always find it relaxing when a pattern gets dropped before it becomes overwhelming - and this is meant from the looking part not the knitting.