make an option in the json for the removal of lower % load models so only the current is shown

If I understand the question, you want a resource pack that only loads the easy to render models (for slower computers)

https://github.com/cam72cam/ImmersiveRailroading/tree/master/resourcepacks

Use the LowResource pack. It blacklists a bunch of the "heavier" stock

Currently all the cargo load models are combined. At 30% load all the models below that will be shown and Legend wants an option to only show the current load model. At 42% ONLY the 42% load model is shown. ^^