I understand the DII is similar to the DIII, which I can comment on. The DIIIVC model uses 6" filters, which I put in the condenser drawer also. Very simple and convenient.
Quote Originally Posted by Deckled Edge
...The filters should be between the light source and the negative, not in front of the lens.
Hope I don't ambush the thread to a different direction for you Neal, but; I guess the spectrum of light wavelengths presented to the negative will be different if the filter is between the light source and neg than if it is under the lens. And presumably this will give different results on the print.
Problem is whenit comes to split grade printing. I found that having to open the condenser draw to change filters part way through the exposure will give shake on the print resulting in loss of sharpness (even using a stop-clock). So at the moment this has me a bit stumped. I've been hand holding filters under the lens for spit grade sprinting.

[size=1]ps. if you're yet to buy Neal, Cl#ss!c Enlargers are very good but expensive. There are bargains around if you have the patience . Mine I found in mint condition at the back of a retail shop for NZ$600 (US$400).[/size]