How soon to get a HELOC

[Brad Estess]

I am about to close on a SFH that will be my primary residence. The house appraised for more than I am paying. I would like to get a HELOC on the house to have some dry powder as I start looking for investment properties. Is there a time period that lenders use before issuing a HELOC after the initial purchase or does it just depend on the lender? Will the lender typically use the appraisal I just got or do a new one? Also, I'd like to maximize the amount available. What ratios are typical for someone with good credit and a good chunk of equity?