Using two LS3060's and an ex 3020 user Please note I am not employed by HPC, any advice or recomendations I give are based on my own experience and are not necessarily the same as HPC's. First point of contact on any hardware issues should be with HPC
For the really complicated stuff I gather you should use a proper CAD package but I find they are a complete black art. Personally I use Microsoft Visio for everything and haven't found it wanting yet (since I found how to do the shape mathematics stuff) simply save the file and then save another copy as an AutoCAD interchange file which can be imported into Laserscript.
I use a mix of Draftsite (Free, pretty much exactly like autocad) and CorelDraw. Coreldraw is great for maniulating text, and I usually use Draftsite in conjunction with coreldraw as I have no idea how to use corel correctly .
As you work in a School you can pick up Corel quite cheap on an education licence. I think I paid around £70 for the full Corel Package. I also paid £75 for AutoCad 2012 on a never ending licence (albiet educational) or you can download every AutoCAD product for free from their website on a 3 year education licence. I thought for £75 on an unlimited licence was worth it