Help with Features

Hello!! I am pretty new to MCreator, only a month or so into learning.

However-

I NEED HELP WITH STRUCTURE FEATURES

I am creating a mod which is inspired by Wonderland.jar

A mod that uses placed features as custom chunks to build a terrain with specific structures

I have the want to be able to place features (each feature is a 16x16x16 cube) in close proxim to one another (essentially touching neighbours, like chunks) 

However when trying to get said features to generate and not overlap one another or occupy the same chunk, they keep overlapping and scrambling up anyway!!

I have exhausted all my knowledge, tutorials and forums at this point

• I have tried the rarity variable
• I have tried and failed to make a procedure to not let the features overlap
• I have tried making sure all air blocks in the features structure are replaced with structure voids
• I have changed the tiers in which order the features spawn in

If anyone could shed light on maybe a procedure that could help avoid this overlapping feature problem or any hints  on how to tweak the features placement confirmation, THAT WOULD BE A LOT OF HELP!!!! AND I WOULD BE VERY GRATEFUL!!!

(Also if anyone does wish to send picture examples, please don't send imagur links, as I am unable to see them - as I am UK based. Thank you!!