I built one a few weeks ago because like you I bought a reamer for it so I had to try it. I hit 3580fps with Retumbo and 105 Amax's but it was warm. I think WC872 or 869 would be the best powders for it but I haven't tested them yet. I have 5 other 6mm rifles so I may not keep playing with it very long.
Wich you were close. I have a very large pile of WC 869 and WC872, in fact they are the reason I bought the reamer. I thought they would be good in the 6-284, but they are way to slow for that round. What is your twist rate and barrel lenth? I`m going with an 8 twist and the longest barrel I can find.
