IMO, there's another way. Here's how I am going to do it.
When TurboTax asks you to provide a method of payment, I am going to check of "Mail in a check".
After the file is transmitted go to PayUSA taxes and you can use your Paypal Credit card there.
I used this website to pay an old installment plan every month for 5 years, its excellent with only a small fee.
