I've been using them for a while with no probs as I usually use DRs anyway. The problem with Drop D is with normal strings or DDTs there is always a difference in feel/tension/tone from the bottom string compared to the other three. It's like the old 5 string issue, when you get the amp set right for the D string, the others dont quite have the same tone and vice versa. I guess that's where Dingwalls come in...
That is part of the charm tho, it's what gives Drop D the heaviness/looseness.
So ultimately the DDTs will give you a little more tension for a better D but maybe a little more on the other three strings which may raise the action a little.
Best plan is just using a heavier 110 or 115 with a standard set. You can pretty much build custom gauges of DR strings from bassstringsonline in the U.S. for cheaper or the same than a set here.
Try a few and see what you like. I've gone from 110/85/65/45 high beams to 110/85/65/45 DDTs but I now play drop C# so I have 115/90/70/50 DDTs which are pretty thick but you get used to it quickly. You may find the tension a bit tight for standard or drop D tho.
The DDTs do also have a different Tone to high beams but not enough to make me change. The only others I found in that 115 gauge were GHS Boomers which are much cheaper and sound decent enough.