In 2011, TCL was 10MB

Around that time the NetBSD kernels with embedded rootfs filesystem I was making were around 17MB

Today, TCL is 23MB

The NetBSD kernels with embedded rootfs I'm using today are around 33MB

That size can be reduced of course

I don't monitor the boot process on RPi with serial console, I only connect after tinysshd is running, so I don't pay close attention to boot speed. It's fast enough

TCL appears to be aimed at users that prefer a binary distribution; also it provides GUI by default

I prefer to compile from source and I only use textmode hence NetBSD is more suitable for me than TCL

For someone who does not want to compile anything from source, it is possible to "customise" (replace) the rootfs of a NetBSD install image with another rootfs. It is not documented anywhere that I'm aware of but I have done it many times

I use a very minimal userland. I guarantee few if any HN readers would be satisfied with it. If I need additional programs I either (a) mount an external drive and run the programs from external storage, e.g., via chroot, or (b) copy them from an external drive into mfs or tmpfs

It depends on how much RAM I have