Rated 5 out of 5 stars

Great addon, Great work! I use it everyday.

I would to set some custom rules like:
-Next 8am (I write at night and most of the time, I want my mail to leave tomorrow morning )
-Next Business day 8am (I write on weekends and some emails should leave when business open)

Thanks

This review is for a previous version of the add-on (6.3.1). 

Please read the user guide:

https://blog.kamens.us/send-later/

You can write functions to implement whatever scheduling logic you want. Some example functions which do things similar to what you asked for are provided. See this section of the user guide in particular:

https://blog.kamens.us/send-later/#dynamic

Rated 4 out of 5 stars

Very nice! Would be even nicer if I had the option to configure

-Send tomorrow morning at 9:00

With ONE button. I believe I would use it all the time
thanks!

This review is for a previous version of the add-on (4.2.4). 

The user guide (http://blog.kamens.us/send-later/) shows how to set this up.

It does require some manual configuration, but I'm not sure how to avoid that. Everyone wants something slightly different from the add-on, and if I tried to make everything everybody requested point-and-click, the add-on would be too large, unwieldy, and difficult to use.