$40K in Market & Currently $160K in Cash – Need Help with Action Plan

I currently have 40K in the market and I'm down 15%. I also have 160K in cash and plan to DCA. How much do you suggest I put every week/month? Is there a rule of thump I should follow? I will be buying VTI, VIG, and SCHD. I consider all 3 ETF's to be solid with low volatility compared to many individual stocks or other ETF's. I'd love to hear your thoughts on how to use my 160K cash during times like these. I will for sure due my dd, but still want to hear your thoughts. THANK YOU!