No idea about making sulfuric acid in the backyard - I am sure it'll be cheaper to buy.
I must say I have browsed first part of the recipe - and I don't like it. IMHO it is full of errors, mistakes and omissions to the point where it is impossible to follow. For example - how much acid per gallon of sawdust? This is crucial information, yet it is not given.
Then - process IS wrong. You can't hydrolize cellulose to simple sugars using concentrated sulfuric acid - it'll just dehydrate it, that's where the organic carbon (coal lumps) is from. Then there will be some hydrolysis, but you don't want some, you need as much as possible. For sure such process requires at least some water in which reaction takes place, not dry sawdust. Neutralization by dilution won't work (not to mention the fact, that pH of used water - as long as it is not some volcaninc or industrial dump - can be for all practical purposes neglected). And so on.
It simply won't work this way.