[Dennis79 (Keith)]

I use a 1.25" cheshire in my 2" focusser and it works fine.

I believe laser collimators need to be barlowed to be effective and the laser itself also needs to be collimated. As far as I can tell brand doesn't matter.

If this is one of your first times collimating your scope it would be wise to have an experienced person with you. I recently found that out the hard way, I collimated based on the written guides and instructions but there is always something you misread, misinterpret or is missing from the guide. Oh and it is much easier to collimate with 2 people as well.