Sorry that you had problems with your installation.Good to hear you got it working! If you remember I was on this path as well some time ago, however I had to finally abandon the tablet-puter-setup after a month or two of usage due to the battery not dealing with heat well (I presume) which lead it to not keeping a charge and constantly rebooting like crazy.
What I wanted to add though, for you to consider was that I found that after some couple of start-ups the joycon would sometimes not "connect" with the tablet thus forcing me to add a physical power-button to the frame so I could flip everything off and on again instead of doing it via the ignition, your milage will hopefully be better though
Indeed I used a nexus 7 (1st gen), with Timur's ROM (USB ROM for Nexus 7) but appearently fast charge was not enough for me and I know the power regulator I used had enough Juice for the tablet and usb-hub (only had joycon connected to it) :/Sorry that you had problems with your installation.
What tablet did you have? I use Nexus 7.