I have fitted converted 749/999 radial master cylinders to my 748R (2000 model) when I had P4 calipers fitted to it, easy to do or just get some 88/1198/1199 master cylinders, that will save you having to convert the 749/999 ones.
Definatly worth doing to get the full benifit of the radial calipers.
You will have to have a set of brake lines made up though.
I have had radial fork bottoms and the same calipers you have now, and fitted discs from an Ohlins kitted 748r/996r/998r, saves using disc spacers.
Have now managed to get hold of a set of monobloc calipers from a 1098
, so they will be fitted over the next few weeks.
I did a post a few years ago regarding the 749/999 master cylinder conversion, but can not find it