USA Cash Out Refi Interest Deduction

[nh767]

I am taking a mortgage against equity on my house (don't have a mortgage currently) and would like to maximize the tax deduction. Mortgage is over the $750K deduction limit. I understand that as long as I put the proceeds I received in an investment account (and can trace it), I can use the interest expense as a deduction against income in that account. Can I also still use the regular interest deduction for the initial $750K (so interest pertaining to $750K will be deducted as usual, and the interet pertaining to the amount over $750K will go against the income in the investment account)?