Double Thumbing using Alternate Picking?

[Leroy La Qua]

I have been working on the double thumb technique for a while now and have developed some fluency - where i am struggling though is in dealing with patterns such as a standard three string major scale shape in triplets (Lets say a C major scale starting on the third fret of the A string with C and D played on the A string, E, F and G played on the D string and A, B and C played on the G string - 3 notes per pitch class) or basically any similar figures that requires movement between strings using odd numbered sequences of notes. I am not sure as to what pattern of thumb up and down strokes to use in order to play this figure?
If playing with a pick I would use stict alternate picking -
DUD UDU DUD UDU etc

Where i struggle with the double thumbing is in the transition from the D to the G strings. If you play through my example the last G played on the D string when ascending is played with a downstoke.Now my question is essentially this - should i be playing the first note on the G string the A with an upstroke or a downstroke?

Clear as mud?

I am curious to hear how other people approach double thumbing in regard to moving between strings and maintaining alternation etc when dealing with odd numbered note sequences

[Grueber]

I add an index finger pluck when needed

[Rattlehead]

I have the same problem as the original post as I am trying to learn the double thump.

I don't know what to do. So far it seems REALLY awkward to play an upstroke on a string if I haven't played a downstroke on it already, so my first note on any string is a downstroke. So that would mean in the C major you describe, I'd play the G on the D string with a downstroke, and then move up to the G string to play an A with another downstroke. Kind of awkward.

I think starting a string with an upstroke would be even harder though, especially if that string isn't the G, because on the other strings you'd have to place your thumb between strings to prepare the upstroke