This is an odd checklist that may take some creativity to use correctly. Your transition level will vary from as high as FL 180 to as low as FL30. We complicate things further by using altitudes for the other steps. I've found the checklist "Defer" option to be particularly useful here.
Everything here is from the references shown below, with a few comments in blue.
[G450 Airplane Flight Manual §2-05-40]
If you have a low altitude transition level, using the electronic checklist's "Defer" option can help remind you when the time comes to leave 1013.
Most operators use 10,000 feet to do this. Some have passengers who come up to the cockpit and say "Let me know when I really have to sit down," or who just ignore the thing altogether.
We get the pulse lights at FL 180.
Gulfstream G450 Airplane Flight Manual, Revision 35, April 18, 2013