Console Display Manager is another great program I found on forums. I downloaded it from GitHub, the authors website seems to be down. Followed that wiki page to configure it, then deactivated XDM and rebooted. I logged in in console and the display manager showed up
CDM works a little different than other DMs. You log in in console (tty1), then /etc/profile.d/zzz-cdm-profile.sh kicks in and you see the display manager. It checks if you are in console, then launches cdm and you choose DE/WM to continue. Basically, you dont need to manually run startx just press the enter key.
I use the default theme instead of cdm theme. You can try those themes (/usr/share/cdm/themes) just fire up cdm in your terminals, use escape key to quit. You dont have to log out only to see the theme. Honesty, the color schemes are not so good in console, thats the reason I chose default them. Its not fancy but still looks good.
The memory usage is slightly smaller, I believe if its written in C, it would use less. It is written in Bash. This was with XDM:
And this was with CDM:
Its about 2-3 MB less but XDM had two more dbus programs running, so its probably 1-2 MB less.
The reason I used XDM was because I didnt want to type startx, now I have removed the XDM since I still dont need to with CDM. My Gentoo is slimmer a little bit.