...One time I played 4 NL200 tables and 2 NL400 tables with a BR of about $3000....
...yeah that did not end too well

But I agree with andy-akb that 8-tabling does not change much in terms of having a higher BR.
IMHO variance is higher while playing less tables and making those "hero" marginal calls. I try and play a straight forward game and probably fold the best hand more often than I should....but it makes for much lower variance.
Maybe one day I will cut back to 4 tables again and stop playing so nitty.