How to safely use buying power for vertical spread on GLD .

Hi Folks ,

I want to reduce my risk exposure and waana stick to GLD , PUT vertical spread with 10 or 20 width for a 30 delta put combo.

Give my buying power , how safe is it to do such trades on GLD ? I'm around 10M Buying power and 1.6M Excess liquidity , as of now I'm not using it so well .

Or is there something else , my goal is to preserve capital ,collect premium and no to less chances of assignment .

Thanks .