The 29.87% rate is artifically low, the actual rate will be much higher to begin with, if the plan is to be purchasing power neutral to the FedGov. The actual rate will be closer to 50% on every purchase of new goods and services.
People can avoid the tax in many ways- buy used, don't buy, fix what they already have, barter, buy with business exemption (good for plane tickets, hotels, restaraunt meals, office (school) supplies, car rentals, baseball tickets, gasoline, auto repair, automobile purchases, office furniture, computers, etc.), buy overseas, or buy underground. There are proably other ways I haven't mentioned.
And a 40-50% sales tax will cause these things to happen, and the more this happens, the higher the required tax rate, and the more it happens. And then we have an income tax. And I won't be happy saying I told you so because mine and every other business will be wrecked.
It's been pointed out to you hundreds of times that your bogus guess of "50% rate" for the FairTax is based on nothing at all but wishful thinking and your own smokescreen. And that is clearly shown by the carefully arrived at derivation of 23% in the paper where all reasoning and mathematical work are shown.
In contrast the "work" you depend upon to spew out such senseless blather is that of William Gale and the President's tax Panel which not only had no reasoning or mathematical derivation, but merely blurted out numbers based upon questionable presumptions and showed nothing of their work to allow checking by real economists.
There is no "40-50% sales tax" except in your dreams. You should pursue your career as a salesman as you'll obviously never make it as an economist.