Booking appointments using the new UKVCAS system

Hi,
Could anyone who has gone through the process of booking an appointment through the new UKVCAS system advise whether it allows you to book an appointment ahead of submitting your application? I'm trying to ensure that I am able to get an appointment right after the submission date?

Likewise, have users found that appointments are easy to come by through the new system or are there significant wait times at the moment?

There is plenty on the ILR boards regarding waiting times, but I'm particularly interested in those submitting naturalisation applications.

Many thanks for your responses.