190XT TRW turbo.

Ok, I’m trying to rebuild my TRW turbo on my 190XT. This is the first turbo that I’ve tried to rebuild I’ve read the service manual several times. I’ve also got both turbos torn down. I noticed a few posts back someone on here said that you need to have them balanced. And today I was at the Diesel shop that I’ve been dealing with; they do a lot of custom pumps and turbos for pullers, asked him about balancing. He told me as long as I mark the compressor and turbine wheels before I take it apart and I don’t change either wheel I don’t need to balance it. Of course the manual didn’t say anything about marking the wheels or about balancing the turbo. I’ve read on the internet (I don’t believe everything on the net) that a turbo can be balanced as a unit or the compressor and turbine separately, and this can be told by the turbine nut if it has been ground on the assembly was balanced. If the nut hasn’t been ground on the wheels was balanced separately so you don’t have to keep them aligned. Am Sorry about the long post but it was needed to understand where I was coming from. My TRW is the later one that the compressor wheel don’t press on, how do you hold the compressor wheel in alignment with the turbine while you tighten the nut and don’t mess up the fins? Also the nut on my turbos don’t have any grinding done on it, do I need to have it balanced as long as I use the wheels out of the same turbo?