Hi @Michael0410 -
The major pairs have narrowest spreads so you can argue they are cheaper to trade. They also have lowest margin requirements.
Your strategy might work better with either high or low volatility pairs: in the majors gbp/jpy is a very high volatility pair, EUR/CHF very low.
Beware of trading closely correlated pairs like EUR/USD and USD/CHF and closely correlated currencies like EUR and CHF.
Depends on your tactics for finding price levels for entry and exit orders. Wide spreads around these time points could trigger everything in sight and the only way to know how wide the spread goes and for how long is to watch it live.