DN, I have good news and I have bad news.
First the bad: yes it was the line you were using in the place you had to use it. Long belly (well, at 55' your line would - - be classified as a mid-belly) lines have a long forward taper and you need lots of line to load up the rod.
Now the good news: The type of circumstance you described is EXACTLY what Skagit and Scandi lines were designed to address. The Skagit (and the Skagit cast) were developed here in the PNW. The Scandi heads ... well, just one guess.
To over simplify, a Skagit cast is a delayed (sustained)
full on water load, even with a heavy sink tip. A cast with a Scandi head is much more of a standard 'kiss and go' anchor.
Bit of personal taste, but a Skagit head will usually be 2 to 2.5 the length of the rod + sink tip or leader. A Scandi head will be 3 to 3.5 the rod length + sink tip or leader. Here-bouts you'll rarely see a Skagit head used with a full floating (regular) leader, but you can if you want.
Vis a vis the Scandi heads most of us use full on leaders or sinking
poly leaders if we want to get down.
The other somewhat limiting factor (one vs the other imho) is a Skagit set up will allow you to cast a fly that's the size of dead bird and weighted like an anvil.

The Scandi's ....... naaaa.
Fred