Hi Al,
The front tapers on Scandi lines are too fine and do not have enough mass at the tip to turn over a sink tip as heavy as T-14, unless it was a very short piece. The front taper of the Spey line must be at least 14 grains/foot to turn over T-14 and then there is the mass of the fly to add as well.
The majority of Scandi lines work well with medium size/weight flys and sink tips up to T-8, around 70-80 grains total. Some Scandi lines have fine tapers, such as the Elixir, AFS Heads, while others have stronger tapers, such as the AirFlo, Guideline PT, Vision Ace Short, Tonic Heads.
T-14 is for very large/heavy flies and deep and/or fast water. For Skagit, there are some lines that have a tapered tip such as the Airflo N.W. Skagit head, which allows the use of T-10, too about 90-100grains. Compact Skagits can handle T-14 and large flys with ease, as there is very little front taper and the line weight at the end of the Head may be 20-25 grains/foot or more.