Depends on your tactics for a start!
Also what you decide to arm everything with!
60 Hormagaunts is a great shock tactic (thats a lot of little gribblies on the table) and can roll up an opponents flank like nothing else but it has to be well supported otherwise it wont get anywhere and a well placed Tank or Close combat unit can stop you in your tracks-but that is why you take things like Carnifex's and Zoanthropes.
A lot of Tyranid armies tend to be one trick ponies, but the knack is finding the right trick.
Overall you seem to have found a good initial balance on what you would like to take but its applying this to the battlefield that counts |