guidelines for fading the open?

I normally trade currencies so never looked at fading the US open of SPX futures. Yesterday I watched the SPX open (2.30 US) and of course there was a tradeable fade, the market rose initially (~3 points )then fell back within the first half hour. I'd be curious on guidlines for this approach, keeping it as simple as possible.
I'll put my initial thoughts below, some ideas based on some previous threads I read on the site.

need stop - set to 10 S&P points from the open (assume initial move is up)

first entry $50 per full point at +2.5
second entry $100 per full point at +4
third entry $200 per full point at +6

close when profit is 1.5 points (to ensure few failures)
or close after 1 hour profit or loss
Dont trade if futures/currency are +- 1% prior to open ie avoid very high volatitily days.

I'd be curious if any of the parameters I have are way off. On looking back over a week or so there were instances of the open not being retested in the first hour so I assume the target profit is key. Is 1.5 a safe target? on average how many days a year would the market keep going in the opening direction and not allow a breakeven situation in the first hour?

thanks in advance