Thanks to Ayesha for sharing these wonderful guidelines:

If you want to follow the guidelines in the Doman Reading book (although they are not necessary to be so exact), they are as follows:

Step 1 Individual Words > 3″ high (tall letters) red lowercase letters (except proper nouns are capitilized ) x 1/2″ width on 6″ x 22″ posterboard

Step 2 Couplets > same

Step 3 Phrases > reduce the size of the red lowercase letters to 2″

Step 4 Sentences with 4 words > reduce the size of the red lowercase letters to 1 1/2″

Step 4 Sentences with 5 words > reduce the size of the red lowercase letters to 1″ high for several weeks and then increase the number of words to 6 word sentences for another several weeks. As long as the child can read this easily, then you . . .

Step 4 Sentences with 6+ words > reduce the print size to 7/8″ red letters for several weeks.

FROM THE BOOK: “The important rule is to observe in this process is never to reduce print size and increase the number of words at the same time. First reduce print size slightly and live with it for a while, then increase the number of words. Do both of these things gradually. Remember the sentence cannot be too big or too clear, but it could be too small and too confusing.

You never want to rush the process. If you did reduce the print size too quickly or increase the number of words too ast, you will notice your child’s attention and interest dropping. He might begin to look away from the printed matter altogether and simply look at you because the card or page is visually too complex for him.

If this should occur, simply return to the print size or number of words you were using right before this happened and his enthusiasm will return. Stay at this level for a good while longer before attempting to change things again.

You do not really need to change the size or color of single words. In fact, we have found that keeping single words larger is easier for both mother and child. However, when you are making books with 1″ letters or 6+words on a page or longer, we recommend changing from red to black print. As words get smaller, black does provide better contrast and a more legible page.

Now the stage has been set for the final most exciting step of all—the book. We have already gotten our foot solidly in the door by creating many little couplet books, phrase books, and sentence books, but if these steps are the skeleton, it is the next one that is the meat. The path has been cleared, so let’s get to it.”

- Ayesha

P.S. I personally use the computer and make the individual words as large as possible and will reduce the size gradually and use the above as a “guideline”. Another interesting point is that the IAHP Reading Kit that has preprinted cards for each step and book have the following sizes that are slightly different from the guidelines in the book:

Step 1 Individual Words > 75 words on 4″ wide x 10″ long cards with 2 1/8″ tall x 3/8″ wide red letters for small words; and for longer words it is 4″ wide x ~20″ long cards with same lettering

Step 2 Couplets > 27 couplets with 4″ wide x ~20″ long cards with 2 1/8″ tall x 3/8″ wide red letters

Step 3 Phrases > 13 phrases on 4″ wide x ~20″ long cards with 1 3/8″ tall x 1/4″ thick red letters

Step 4 Sentences > 5 sentences that are 4″ wide x ~20″ wide cards with 1 3/8″ tall x 1/4″ wide red letters

Step 5 Book > Book entitled “Enough Inigo, Enough!” with 9 7/8″ wide x 7″ tall pages with 1/2″ tall x 1/16″ wide black letters

So, as you can see – their own kit does not match exactly what the suggestions are in the book – it is a guideline! No need for rulers!