Just to chime in with my (limited) experience with my f/4 scope...
From my research and experimentation, a simple cheshire is not sufficiently accurate to get you in the ballpark for imaging. At best your stars will be slightly off, and you'll notice it in small and large stars in the FOV.
A Barlowed laser is an "accepted" means of checking/collimating the primary, but a sight tube, and autocollimator are the tools you'll need for bringing the secondary into alignment. It's quite a chore if the mechanics of the scope have any flex, slack or play whatsoever, and in such a case won't give you consistent results as it tracks an object across the sky.
By "accepted", I refer to the methods/techniques discussed at length at that site over the big pond. That doesn't mean it's right, or the only way, just that's what you'll see when digging a little deeper. High-precision collimation of fast newtonians doesn't seem to come up very often here...or I'm completely missing it