Recently, my friends and I wrote a mashup contest. We gave the link to others to register, however I encountered two problems.

Firstly, registration is only open within six hours of contest time. So, when a user gets invited to a mashup, they are not able to register until six hours before contest starts.

Is there any way to set a custom registration time (e.g. 3 days before the contest)? If there isn't, I think this would be a cool feature to add to mashup contests.

Secondly, after a user is successfully registered, they would receive the pop-up "You have been successfully registered", and they would get redirected to this page. This means that they have to paste the contest link / invitation link again in order to view the contest page (in the format of https://mirror.codeforces.com/contests/[6-digit number]). This can be confusing and inconvenient to mashup participants, especially those who encountered this problem the first time. Perhaps they can stay on the page instead of being redirected?

This is not my first time writing a mashup contest (and encountering these problems); I have written a few before.

I have seen this blog talking about a similar issue. However, the registration time problem hasn't been solved, so I would like to hear from your thoughts.