Medium to Large enlarger base/Lizard Mount Compatible

I've been using some minis for riding lizards for D&D, and there is often confusion because the base that comes with my minis does not fill the entire space that a Large creature fills, so i decided to remix this other base to be a bit more multipurpose.

I modified the original file slightly for a larger base size (to be compatible with some minis I have made) and added a slot to be compatible as a base for the following:

https://www.thingiverse.com/thing:2254549
Silhouette Minis - Set 9 - Lizard Mount for Ride
by jpacek

Update: Still tweaking the size of the slot for a tighter fit so it won't be so wobbly (I'm not permanently mounting it in the base).