I just finished mine couple days ago, definitely a smaller brother of yours 
I plan on using this 8" by 7" vacuum puck on some smaller projects + making 3 more for a bigger ones.
Also doing a tiny one tomorrow, 5.5" x 3.5" for business cards engravings, idea from this YT : https://www.youtube.com/watch?v=SdSVMygb450&t=1s
I would say the hardest part was finding pipe fittings coming out from the pump. Things you learn when you find out the flare thread is not the same as NPT
What projects do you use your vacuum system for?