Decided to build a wake up sequence with lights that transition until bright/day-temp, an alarm via Google Nest display in our main bedroom, and then added a snooze function. Settings are made via connectors driven from a section of our dashboard. It's working nicely and just thought I'd share in case it helps anyone else or provides some inspiration.
All comments for improvements welcome 
Dashboard settings:
From left to right, main alarm on/off, snooze on/off, the wake up time for weekends and weekdays at the top, and the snooze time and number of snoozes. These connect to Global Variables using connectors (which is really cool functionality!).
I use 2 simple little rules to make sure that if the main alarm gets turned off then so does the snooze, and vice versa if the snooze gets turned on then the alarm must be on...
Global Variables:
Here's what I use...
The 2 with 'start' in them are the start times for the sequence, for weekend and weekdays. They are simply 30 minutes earlier than the times set on the dashboard, set by the following simple rule...
And another simple rule to set the snooze Time (which had to be in seconds for later use)...
The Main Routine:
Here's the main RM rule, quite a simple flow really...
I bring the lights up in 2 stages because I found otherwise they brighten too quickly. So I split the routine into 2 x 15 min phases, first slow, then more fast. It works very nicely. I use 2 Withings sleep pads to test whether we are in bed or not. These work very reliably. I also use these to arm/disarm night HSM.
Then if Snooze is on it kicks off another rule...
This includes some rude statements played over the Google Home device to encourage us out of bed (excuse my British sense of humour) 
I also play an alarm sound streamed from an RPi downstairs which is running Apache web server (literally a 20 second thing to set up and so cool). I now have dogs barking along with my Aeotec siren bell when my front door motion sensor goes off using the same technique lol. Our neighbours are quite confused because they know we don't have any dogs
