I found a way to make it work from my startup-sequence.
This code will launch Tiny Launcher before your system loads Workbench, giving you quick access to your demos and games and stops your Amiga using lots of resources. I also added an assign because it fixed the problem with Workbench (Scalos) messing up after exiting Tiny Launcher.
My setup is running Tiny Launcher from the C folder of my system drive on a Classic Workbench v27 Full installation. I cannot guarantee that this will work as well on other setups, so don't blame me if it doesn't work on yours. All the following is to be used on your own risk
Open up the S:Startup-sequence file in an editor and put the following codes in order just before the C:LoadWB line, or alternatively put the lines somewhere in your User-startup file:
In the Lite version of Classic Workbench (v27) it already runs NewIcons in the User-Startup, and the problem with Scalos if also not present as it runs a real Workbench, so here you can skip the following changes and just put in your TinyLauncher executable line.
This line runs NewIcons so Tiny Launcher can utilise it. If you get a message saying "Already running!", you already have NewIcons in your startup files, and then you can skip it:
Run <>NIL: C:NewIcons
This line is needed, as NewIcons does not seems to initialize before the cli or wb screen is shown:
Echo "Running Tiny Launcher"
The following line runs Tiny Launcher.
If you are using another version of Tinylauncher or another path, please change the name and path of the exe file to match your setup:
I added this assign because it fixed the problem with Scalos messing up after running Tiny Launcher at startup. You can try running without it and just put the line in if your Scalos doesn't run properly after exiting Tiny Launcher:
Assign >NIL: ENV: RAM:ENV
If you get a System Request saying that "Intuition is attempting to reset the Workbench screen.", you have probably put the lines too soon in your startup-sequence. Move the lines down before C:LoadWB or into the User-Startup file, and you should be good.