Generally one can say, that the straighter the limbs the longer they need to be. The design/profile of the bow, the draw length, the length of the bow and the length of the riser all connect together.
If you want to build a short d/r-bow with a length of 58" and the desired draw length is 28-29" then you might want to make the riser only 16" to make sure it doesn't stack to early.
IMHO a longer/bigger riser has some pros. Personally I like heavy bows. With a longer riser and a heavy wood this can be done very easy. The heavier the riser is compared to the limbs, the smoother the bow will shoot. The bigger the riser is, the easier the grip can be adapted to the hand of the one who's going to shoot it. No matter what kind of grip he prefers.
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Andy