Thanks,
I just wanted to back report that diluting with THF worked well.
40 mmol 10% solution of 2,5DMNS in THF was succesfully dissolved and reduced using 350 mmol 3.5M red-al/toluene solution diluted with 100 ml THF.
However another reaction where 40mmol of 3,4,5-trimethoxy substrate was dissolved in 100 ml THF and added to 100 ml 3.5M red-al/toluene diluted with 100 ml THF slowly over the course of 10 minutes made the whiteish solution turn deep red 30 minutes after the addition had completed another 25 ml vitride was added and things are refluxing for about 18 hours now. taking a drop of the reaction mixture and adding it to water causes some fizzing, perhaps the reduction requires a long reaction time ? (in pihkal the lah reduction took 48 hours).
As for the purity, tlc on the nitrostyrene gave a single spot at Rf 0,62 using ethylacetate with a mp of 117-118 Celcius