No reason to buy 20 trueborn. You get the 2 DL right off the bat.
So buy your minimum squad of 5. either with a raider, or park them on their own.
I used to buy the squad of 3 with 2 DL quite often in old dex. it was 96 points for an extra 2 lances. They survived a little while as they were rarely target priority for my opponent.