I'm 58 and spent my life FF lakes with my dad for fish we eat. Sport never entered into the equation. We built our own leader for bass/crappie and never thought twice about the 'science'. I just got through looking at 'LEADERCAC' and this has to be the biggest load of BS i've ever read in my life.
My dad, being a person who flyfished and saw what happened when he built a bad leader spent his last days talking fish with me, about leaders. He used a 5wt steel truetemper rod with a level flyline. (not W/f or D/T) He caught fish after fish on his system, that I find it reasonable to accept what he said was true.
IF THE TIPPET WORKS THE FLY AND THE LEADER GETS IT OUT THERE, THEN IT'S RIGHT. Damn, now that's to simple for something that leader calc has you breaking down into tying 6" sections of line to the tippet.

We looked at the formulas of 'LEADERCALC' and here were his comments;

You don't need to get that taper to make a good cast..."somebodies makin money somehow handing inexperienced FF bad info"......Then he went on to think the manufacturers of tapered leaders have fabricated this system to complicate FF and have people throw their hands in the air and just buy their friggin tapered leaders.
HERE'S THE LINE I LIKED BEST;
COMPARE.........................make your own leader, and count from 100 the bad casts.....FF'ermen selling a product say "the FORMULA was wrong"
Compare..........................the bad casts from 100 on a manufactured tapered line...crap you still can't cast...time to take some lessons.......IT HAS TO BE YOU!!!!!!!!!!!!!!!!!!!!!!

This line of thought goes from every aspect of the 'INDUSTRY' that sells leaders.

Hey, my old man was a drunk, even though he caught fish on a flyrod everytime he went out what the heck could he know....right????
Here was his first comment on 'LEADERCALC', How can you segment 10 line dimensions down to a taper without calculating in the effects of the "ALL THOSE" knots affecting the entire system of tapering down..................YOU CAN'T!!!!!!!!!!! they affect the dynamics so much that 5 pcs of line in 6" increments are just plain idiotic.
He documented the butt/midsection and tippet as 3 pcs.....never more than 8'.........with the butt and mid-section remaining the same for the set-up......the tippet always changable for the fly weight. I guess this is where experience was required.

WHAT??????????????? EXPERIENCE.......BS, A new fly fisherman should be able to buy a book and have the exact guidelines give to him so he catches fish....

Today being the drunkin FF my dad was, I sit, cast and catch fish............all by feel.
My 8', 3 piece leaders turnover and get me to the fish with ease.

How we have complicated one of the most beautiful things in the world to make a dollar astounds me......then I see how screwed up this world is and can understand how stunningly stupid people are who have taken something so simple and ruined it.
Go back to the basics of FF;
Make a 2 or 3 piece leader, cast it out for a month or 2. see what it's doing and if you don't catch fish.....MODIFY it..................... This is the true art of casting a flyrod to catch fish. Good things take time to happen, sometimes we are lucky enough to have people pass on what tey know for no reason other than the love of what they do.
If you're not as lucky as I was, EXPERIMENT with the 60/20/20 method and make a few years of mistakes before you can say........OH LORD, I UNDERSTAND!!!!!!!!!!!!!!!