I have looked at fitting it inside the cross-slide, I can't see where I would fit it, there is the slot for the taper turning attachment & holes where the cross-slide feed bolts to, see the pictures, without the attachment fitted. Sorry for the mess, I was mid production of a batch of nuts.
The underside looks like this, taken later, when I had finished the nuts.
More details of it are to be found at lathes.co.uk.
The Machine DRO attachment for the normal cross-slide extends the cross-slide out the back, you then machine a slot in the main casting & extension for the magnetic tape, this would interfere with the taper turning attachment.
Mounting the scale on the side would probably mean 1" of lost travel towards the tail-stock, I already find I am often against this as I try to keep the tailstock in as far as possible so it has the support of the body.
It may be that what I am trying to do is not practical.