Multitexture map does not support procedural maps. I am using it quite often. For fictional paving are plugins like this or VP cross map good, but when I need something specific, or I dont have much(or non) good photo references from original product, then procedural maps are handy.
There is another solution how to add probability in distributing IDs - add MaterialByElement modificator on top of RC. It unfortunately supports only 8 IDs, which is enought in this case, but if I will need more than 8, hopefully somebody can create similar tool using 3dsmax MCG tool for more than 8 IDs
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So for now I am quite satisfied, parsing time drops from 40s to 10s and I can adjust IDs probability.
It seems to be good tool for quick creating new real paving in comparisson with VP omnitiles.