In theory you should be able to fit a clutch without the tool as from new out of box it is in the correct position but it can be knocked out of its correct new setting if the box has been dropped or kmocked about as I found out when replacing a clutch unit on a Chrysler Seebring.

So my advice is for £25 is it worth the extra risk of having to waste 3-4 hours having to do it twice.

Also there is a way of seeing if the clutch pressure plate is set ok out the box from looking at the spring tension of the self adjusting mechanism. Ring LUK or SACHS and they will email you information on there types.

Thanks
Lee