To create a pro-form that uses just PayPal Express Checkout, change the pro-form's "accept" attribute to just "paypal": accept="paypal".
The pro-form genearator adds all the cards to that attribute by default. The cards will require you to have PayPal Pro, though. See these articles:
http://www.s2member.com/kb/paypal-services-a-quick-comparison/
http://www.s2member.com/kb/paypal-pro-payflow-dprp-express-checkout/
You can test with 1 cent transactions in the live account. I don't prefer to use PayPal's developer sandbox, though. See my video on that: https://www.youtube.com/watch?v=08t45PYeHxk
I hope that helps. :)