Simple Payplan 4 setup

We have been using Payplans for some years now and have, through the years, got the system to work the way we want.
However, the process is a bit clumsy and we were wondering whether we should re-look at the whole process when we upgrade to PayPlans 4.

We want to use the following process:

• When a user signs up, they can select a free (forever) or paid (limited time) plan.
  
• If they select a paid plan, they then have an online or offline payment option.
  
• If they choose the offline payment option, we want them to still be able to access the site as if they had selected a free plan.
  
(This seems to be where the complexity comes in. Often there are delays before we are notified that a payment has been made or if the user changes their mind and never pays. We want then to still be able to login to the site while they wait, but with only free access options).

• When a paid plan expires, they automatically fall back to a free plan.
  

The main function of the paid plan is to set the Joomla usertype to paid and the EasySocial profiletype to VIP.
When the paid subscription expires, the Joomla usertype is reset to registered and the EasySocial profiletype to Basic

What would be the best way to set this up with Payplans 4?
(We are still testing PayPlans 4 and have identified some bugs, so we aren't ready to go live wsith PP4 yet)