This doesn’t seem to be supported right now. Can you open an issue on github?
As a workaround, you can use eg. OptunaSearcher or HyperoptSearcher with random samplers to achieve a similar outcome to the BasicVariantGenerator (though tune.grid_search is not supported with those).
Another workaround is to pass constant_grid_search=True to the BasicVariantGenerator and a "repeat": tune.grid_search(range(num_repeats)) parameter to the config/param space. This will sample the random values first and then iterate through all grid search parameters, keeping the random values constant.
If you have more grid search parameters, this may not be exactly what you’re looking for - let us know!