ECW idea.

[Kommando_J]

Here's my suggestions;

For the defenders

The firelock storming party- http://store.warlordgames.com/collections/the-english-civil-wars-1642-1652/products/thirty-years-war-firelock-storming-party

For the sniper - http://www.warlordgames.com/model-of-the-week-pike-shotte-marksman/

For the attackers:

Some dismounted dragoons and a large bomb - http://store.warlordgames.com/collections/pike-shotte/products/royalist-parliamentarian-petard-assault-team

And engineers of course - http://store.warlordgames.com/collections/the-english-civil-wars-1642-1652/products/pike-shotte-engineer-working-party