Using HELOC - Overdraft vs manual transfer vs HELOC-check

I have a checking account and a HELOC account and was wondering what is the best way to give checks to external parties.

 

These are 3 options I am considering -

1. Give a check from checking account. This account is protected for any overdraft by the HELOC account. If the balance in checking account is short, then the overdraft amount is drawn from HELOC directly by the bank.

2. Manually transfer money from HELOC to checking account in advance, when anticipating that checking account will have an overdraw.

3. Give check from HELOC account.

 

Which one is the best? How does each affect my credit score?