I have just posted this new Monticello configuration to the "MagmaTester" project of squeaksource. I recommend using this for your development projects.
This rolls up several fixes and enhancements including, most recently, a major improvement in single-clause query performance. #size and #at: are now handled in a single, brief, server call! This is the way it was in Magma years ago when single-clause was all that was supported, before #where: came along.
Now, there are two subclasses of MagmaCollectionReader. MagmaCollectionFilteredReader and MagmaCollectionOptimizedReader. #where: will automatically determine whether your where: is a single clause and, if so, answer back the Optimized. The API is exactly the same, but Optimized will perform roughly 100X faster than Filtered with #size and #at:.
This, of course, creates a need for conversion if you have persistent readers in your repository. They will have to be converted to an instance of either subclass, but that conversion script is not yet written.
Enjoy, Chris