Hr Stacheldraht,
I agree with your terminal figure of 800,000 ish volunteers in '45 - my sources are a report from the Ministry for the Eastern Occupied Territories dated Jan '45 which says 748,000 plus 60,000 odd Estonians.
There are soo many reasons why the Osttruppen situation has become blurred, not least of which is the sellout of them by the British government post WW2 (ie post Churchill) and the lack of a view on their possible use against Communism a la WW1. Churchill was all in favour of carrying on his White Russian war post WW1... the Americans realising this much too late.
As for attrocities, well, I saw what I always say, in the East you can only say the victors write the history. Everyone involved was as bad as the others - in this part of the world slaughter of your neighbours because of some centuries old grudge is par for the course - see Yugoslavia for a good example of this. Do not think for one minute that every Osttruppen was united as POA! The Germans quickly identified this problem and hence the various factions that made up the Legions.
Frw. Koslov