I struggled with the Sunlu 250g spools and tried a few different spool holders. I found the 'AMS Lite Small Spool Securing Cap' by dandcmckay and it worked but the spool was extremely loose and I got a few tangles. I made this sleeve to go along with that adapter. It fits the bare spindle of the AMS Lite and fits inside the 250g spool but not tight.

It is 2 parts, takes about 30g of filament and a friction fit, but I did put in holes for you to screw it together. I printed a few and screwed them on to make changing colors faster. I used #4 x 1/2" Pan Head Philips Sheet Metal screws as they are self tapping and easy on the filament. Sorry, a beginner and not able to make threads yet. See pictures for visual.

Steps:
1. Put the 2 pieces together on either side of the spool and click them together.
2. Secure the spool and adapter on the spindle with the 'Securing Cap'.

NOTE: The 'AMS Lite Small Spool Securing Cap' by dandcmckay ONLY works on position 2 and 4 on the AMS Lite. These are the YELLOW colored spindles. See his post in Makerworld for details and STL files.

Thanks to dandcmckay for their 'Cap' and the spool does not fall off the spindle anymore.