Oracle Database Discussions

I am currently working on a project with a large amount of metric data in a table that is partitioned by week, and then subpartitioned by one of 26 different machine types. For the most part, we get the same amount of data each week, so the partitions are about even in size. The subpartitions, on the other hand, have vastly different sizes (hundreds of rows compared to 10's of millions of rows), and in most cases, queries span the subpartitions.

Would these subpartitions degrade my performance when querying using multiple subpartitions? If so, is there a best practice for how evenly distributed data needs to be in order to get benefit out of subpartions?

Thanks,
Jon