The dash is fine for light wind kiting. Hydrofoils are weird in that once you are at speed, the kite barely does anything, it sort of sits there parked in the sky. If you are racing and you need VMG and have to push hard on the foil to go upwind at speed then yeah the kite matter. For typical hydrofoiling, though a bridled C shape kite like the dash is perfectly adequate. Once you start to get down to sub 10 knot wind speed you need a foil + foil combo anyway, as tube kites start falling out of the sky. You should be good on that 14 Dash down to about 10 knots and below that you will need a foil kite. Sure the mono strut and no strut tube kites are nice but I think everyone who pushes their lower limit eventually goes foil + foil to catch the smallest breath of wind. For ordinary low wind conditions just use your 14 or 12.
I estimate my C2 17m to be able to fly in 4-5 knots and my LF Solo 12m to fly in 6-7 knots.
The reason you'll see people going to foil + foil isn't for absolute low end, it's about how the kites generate relative wind. Light LEI kites aren't high aspect ratio and don't generate much apparent wind while foil kites are super high aspect and also light weight so they generate loads of relative wind thus allowing you to go much faster in light wind.
If you are happy going slow on your foil board then light LEI kites are just as good as foil kites at half the price.