[Device Reviews and Information] thecoolkid:
I have been playing with the same tutorial and successfully repartitioned 2 tablets, but I haven't had the time to post about it. The process is pretty straight forward and indeed you can't use SP Flash Tool afterwards except "format all" option, so I made myself a couple of tools to backup all the partitions that can't be flashed with SP Flash Tool and another one for restore. Another tool is to set up parted while you are in TWRP and to format vendor, system, cache and userdata afterwards (optional), because I was resizing vendor to 500 MB (there's some wasted space left by CHUWI, no harm in reclaiming it since there are no updates), system to 4 GB (4096 MB), cache to 100 MB (as per Google recommendation on AOSP site: 50-100 MB) and userdata to whatever's left. In the future I might write a tool for automatic repartitioning of the tablet, we'll see ;)

Some tips:

Follow the Hovatek guide, but remember:

1. Don't delete sdrpmb and flashinfo partitions, they are at the end of memory, but contrary to the guide you don't have to delete last partitions

2. You can remove just 28-31 partitions (vendor, system, cache, userdata) and the newly created partitions will "fall into place".

3. In parted you can switch units by a "unit" command followed by a unit (MB: 1000 MB = 1GB, MiB: 1024 MiB = 1 GiB, B: Bytes). I recommend using MiB for vendor, system, cache if you're pedantic like me ;) and then switching to Bytes for userdata partition to fit it exactly in the free space left.

4. I advise you to make a TWRP backup in case smth goes wrong (not partition image, compressed file backup) of boot, para (restore for recovering from bootloops, it contains a flag of unsuccessful boot and will reboot you to recovery even if you have a working system), vendor and system and also all device specific partitions that can't be flashed with SPFTool (you can use my tool for that).

5. You'll need vendor backup to restore it into smaller partition since the image backup won't fit. Offload the TWRP backup onto the computer. You'll lose access to all data stored on removed partitions!

6. I advise you to save parted output (partition list with their sizes, starts and ends) as text in a text file for multiple units (MB, MiB, B) for reference later, both before and after repartition. It'll make your life easier ;)

7. Your newly repartitioned device is best enjoyed with Modern Boots :D

FYI: My tools require PATH system variable to be set up to include ADB tool, so it can be executed from any folder as simply "adb [command]", if you don't have that edit the scripts to fit your environment. You have to be booted into TWRP with ADB enabled to use the tools. If you formated your whole memory with SPFTool, first flash all partitions in SPFT then flash TWRP then boot to TWRP and finally you can restore IMEI and DRM keys or whatever there is using restore tool ;)

FYI 2: Usefull terminal commands (prefix with adb shell if executing from adb):

# sgdisk --print /dev/block/mmcblk0

list all partitions in TWRP without parted

# parted /dev/block/mmcblk0 [unit MiB]

list all partitions in parted in automatic units [optional unit change, you can also change units later]

Have fun! ;)