Hey Allan, get NEWT software to work out your secondary mirror size. Can't see it listed in the links or software pages but a quick search will find it. I shortened mine for the DSLR but the mirror was oversize in the first place so no problem.
You also should get the kit to centre spot your primary mirror with a yellow "hotspot" - it includes the spotting template and the spot. If you decide not to get an Autocollimator, then you could get the triangle spot rather than the "hotspot".
Now, many say that you could stop at the Cheshire, that the Autocollimator would add a level of precision that is insignificant at f5. But if you can afford it and have the time to spend at the scope (a few more minutes at most) and like to have what you feel is the best you can achieve, you can get the Autocollimator as well.
If you want to save money, and space in your kit, ask Jim Fly to advise. There is a model of the sight tube that includes a reflective ring so it can act as a Cheshire as well. I haven't used it. Also there are various packages of tools and spotting templates - ask Jim which is the best mix for your needs.
ps. get one of his red clip-on LED illuminator lights as well.