Hat decreases

How-to Questions
1

I am working on a version of Half Dome from Knitty. Someone was kind enough to post the directions for decreases to knit the hat in the round.

Instead of working in stockinette I am working in a pattern of:

Row 1: YO K2tog
Row 2: purl

I would like to keep this pattern for the entire hat (instead of switching to stockinette for the crown). Can I do the decreases on the purl rows? If so, can someone tell me what I need to change?

MARKER METHOD (using circular needles and/or DPNS)?Place one marker for start of round and three contrasting markers at intervals of 33 stitches each. ?
Next round: K1, K2tog, K to 3 st before 1st marker, SSK, K1. Slip marker, K1, K2tog. K to 3 st before 2nd marker, SSK, K1. Slip marker, K1, K2tog. K to 3 st before 3rd marker, SSK, K1. Slip marker, K1, K2tog. K to 3 st before round-start marker, SSK, K1.?K one round plain, then repeat these two rounds 13 times. [20 st on needle.] Remove markers on last plain round. ?
Next round: K1, S2KP, K2, S2KP, K2, S2KP, K2, S2KP, K2, K1. [12 st on needle.]?K one round plain. Next round, K2tog, K2, SSK, K2tog, K2, SSK. [8 st.] Finish.

2

Since no one’s responded yet, I thought I would mention that charting is supposed to be a good way to figure out stuff like that. (Or so I’ve read.) I have absolutely no experience with it, so I can’t help beyond that, but it may be something you could research.