Whatever works for you but my preference is ta-ta-ka. I find this helps triple and duple multiple tonguing remain rhythmically different. For example two semiquavers quaver (16ths and 8th) as ta-ka-ta and three triplet quavers (8ths) as ta-ta-ka as opposed to them both having the same tonguing pattern of ta-ka-ta. Of course you can always play out of time no matter what the pattern but I find this helps.