Doesn’t the new tax law remove any tax deduction for HELOC interest where the money is not used for home-related purposes?
https://www.irs.gov/newsroom/interest-on-home-equity-loans-often-still-deductible-under-new-law
Or are you willing to pay the non-deductible interest on the HELOC assuming better returns on the SEP and solo 401(k)? I assume your financial advisor is taking this into consideration?