I started SWFF when I was a child, fishing for sea trout in the west of Ireland. I followed Falkus pretty much to the letter, so fished with a 10ft 6" Hardy Invincible, and slow sinker. It worked great, and I caught sea trout (on Sunk Lures) mackerel and bass consistently. Later "graduated" to various Hardy Fibalites and Bob Church rods: absolutely Meyre's "Grafham by Sea"!
I know fibreglass has got a LOT better, but so has graphite: I simply wouldn't ever go back, even for the nostalgia. There are fewer fish in the sea, and the conditions that I fish in West Wales typically need quite heavy and/or high density lines, turning over big (and sometimes very heavy) flies in high winds, and managing the line in strong swell.
I think here in the UK we make life quite hard for ourselves just doing SWFF. Personally, I think using sub-optimal tackle (i.e. a soft/slow glass rod; my go-to lines are a #10 intermediate and a 350g sinker) is a handicap too far: I am just not a good enough caster for it to be worth it.
(For the record, I LOVE glass for rivers and streams, and have two: a Hardy and a Maxcatch. The letter is actually the better rod for me!)