I think the consensus of opinion appears to be that for the period in question the Dutch weren't uniformed or if they were then at the comissioning captain or colonel's whim. French uniform details are reasonably easy to find, at least for the end of the period. The English army is quite well documented, the Spanish you can take from the Vinkhuizjen plates from the NYPL on-line collection.
Yes, they are limited in terms of pose but that doesn't worry me as much and if you want some variety, there's the largely compatible Dixon range, also sculpted by Mark. You can raid Brigade Games King Phillips War for a few more, the Officers from Artizan's pirates and or the new Front Rank range. The limited dolly use has almost become a trademark with Mark, look at the BoB ranges.
Ok call me a fan boy but I love these, they've inspired me to finish my English army and expand my continental forces. If he goes ahead and does Spanish and maybe some Swiss guards I'll be a very happy man.