ETFs vs individual stocks #2.

I looked at a blog for the first time today & liked the post on covered calls versus DOW 30 stocks.  (Blue Collar Investor - covered calls, DJIA).  I even added BCI to my blog's reading list.  In my IRA, I sell the monthly cash secured puts against broad based ETFs to help me buy, & then, after assignment to buy the ETF, I sell the monthly covered calls to help me to sell it.  I've considered using individual stocks, & even reviewed the BCI post's idea at today's market close.  I did the arithmetic with DIA ($248.70), the ETF that invests in the DJIA's 30 stocks, & with WMT ($102.42) - Walmart - one of the DJIA's stocks.  To maintain apples to apples, both equities have a current dividend yield of about 2.1%; & I selected the 11/16/18 puts & calls that were about 2.5% out of the money.  I calculated what I call the premium yield - for puts, I divide the premium's BID by the strike price (the amount of cash reserved); for calls, I divide the premium's BID by the equity's market value.  Using the time until expiration - 17 days - I annualized the premium yield.  For selling puts, DIA's annualized premium yield was 25%, WMT's was 39%.  For selling calls, DIA's was 18%, WMT's was 36%.  I'm sure I'll re-visit the individual stock idea for my IRA, but how do you feel about covered calls (cash secured puts) versus ETFs?