Re: Wanna build a Marshall type head cse
Go to the source ... take a tape measure, pencil and paper to an actual Marshall cabinet that appeals to you and take measurements, make a drawing. Also make a drawing of your chasis, with measurements. If there are discrepancies, make minor adjustments to your plans for the head shell.
Or design a rack sleeve that will hold your amp, then 'Marshall-ify' the design, then purchase all the necessary Marshall fittings and tolex for it.
Such projects are all about the planning. Plan it right and building it will be easy.