Full justification makes for slower reading because spaces between letters are different and interupt the flow. Also it can lead to spaces that can have other things added in later – not usefull in legal docs!!

Fonts always seems to rear its ugly head. I have seen people who should know beter argus against Times New Roman. That font has serifs. We do not read using individual letters, we read by picking up word shapes and a sana serif font does not portray a good word image. I have seen demonstrations of text that have the correct letter at the beginning and of each word but the letters between those in each word are all jumbled up. When you have read a line like that you can actually read text set out that way with little difficulty. Try tihs for szie and see how you can cpoe wtih ervyitenhg msesed aobut, of crusoe you hvae to hvae wrdos of more tahn 3 ltrets!!
Cheers

2.13Justification and margins

Only the left-hand margin should be justified. Right-hand justification should be turned off, leaving the margin unjustified (ragged right), so that correct word spacing is preserved.