This may be of interest:
https://www.dmt-nexus.me...aspx?g=posts&t=23020do not filter after reduction, and you should be fine, DMT salts are very stable at boiling temperatures, they will certainly not evaporate.
Are you working with a separatory funnel? If so, I wouldnt reduce more than you did just because as some people say in the linked thread, it can happen that some stuff precipitates when you add lye and this may block your sep funnel's stopcock..
Better work in two runs or so and keep that amount you have.
If youre not working with separatory funnel, you could probably get away with reducing further to 3l without a problem.. again, just dont filter after reduction