Norma.
I was able to take the information you provided and to come up with the dough formulation that represents a combination of the Detroit offspring dough (5.18 ounces) and the Boardwalk offspring dough (12.8 ounces). The total dough offspring dough weight is 17.98 ounces. That is for a single 17.5" pizza.
For the record, this is how I came up with the combined offspring dough formulation as set forth toward the end of this post:
First, I had to recreate the original Detroit and Boardwalk dough formulations that you usually use to be sure that I had all of the right numbers. For example, in doing this I saw that you used Kosher salt (presumably Morton's), not regular table salt. Also, for the basic Detroit formulation, I concluded that you made 13 dough balls each weighing 9.5 ounces. For the Boardwalk dough formulation that you usually use, you used a thickness factor of 0.08 for 15 dough balls. In both cases, you used a thickness factor of 1.5%. I assumed in both cases that the same flour or flour blend was used. Using the Lehmann dough calculating tool at
http://www.pizzamaking.com/dough_calculator.html, here is a summary of the two dough formulations:
Original Detroit Dough FormulationFlour (100%): Water (75%): IDY (0.70%): Kosher Salt (1.75%): Total (177.45%): Single Ball:
 2002.67 g  70.64 oz  4.42 lbs 1502 g  52.98 oz  3.31 lbs 14.02 g  0.49 oz  0.03 lbs  4.65 tsp  1.55 tbsp 35.05 g  1.24 oz  0.08 lbs  7.3 tsp  2.43 tbsp 3553.74 g  125.35 oz  7.83 lbs  TF = N/A 273.36 g  9.64 oz  0.6 lbs

Note: The above dough formulation is for 13 dough balls, each weighing 9.5 ounces; bowl residue compensation = 1.5%
Original Boardwalk Dough FormulationFlour (100%): Water (62%): IDY (0.50%): Kosher Salt (1.75%): Oil (1.5%): Sugar (0.8%): Total (166.55%): Single Ball:
 4986.8 g  175.9 oz  10.99 lbs 3091.81 g  109.06 oz  6.82 lbs 24.93 g  0.88 oz  0.05 lbs  8.28 tsp  2.76 tbsp 87.27 g  3.08 oz  0.19 lbs  6.06 tbsp  0.38 cups 74.8 g  2.64 oz  0.16 lbs  5.54 tbsp  0.35 cups 39.89 g  1.41 oz  0.09 lbs  10.01 tsp  3.34 tbsp 8305.51 g  292.96 oz  18.31 lbs  TF = 0.0812 553.7 g  19.53 oz  1.22 lbs

Note: The above dough formulation is for 15 dough balls based on a thickness factor of 0.08; bowl residue compensation = 1.5%
I then used the bakers percents for the two dough formulations but using the 5.18 ounce dough ball weight for the Detroit offspring dough and the 12.8 ounce dough ball weight for the Boardwalk offspring dough, but with no bowl residue compensation. This yielded the following two dough formulations for the two offspring doughs:
Dough Formulation for Detroit Offspring Dough Ball (5.18 Ounces)Flour (100%): Water (75%): IDY (0.70%): Kosher Salt (1.75%): Total (177.45%):
 82.82 g  2.92 oz  0.18 lbs 62.12 g  2.19 oz  0.14 lbs 0.58 g  0.02 oz  0 lbs  0.19 tsp  0.06 tbsp 1.45 g  0.05 oz  0 lbs  0.3 tsp  0.1 tbsp 146.97 g  5.18 oz  0.32 lbs  TF = N/A

Note: No bowl residue compensation
Dough Formulation for Boardwalk Offspring Dough Ball (12.8 Ounces)Flour (100%): Water (62%): IDY (0.50%): Kosher Salt (1.75%): Oil (1.5%): Sugar (0.8%): Total (166.55%):
 217.88 g  7.69 oz  0.48 lbs 135.09 g  4.76 oz  0.3 lbs 1.09 g  0.04 oz  0 lbs  0.36 tsp  0.12 tbsp 3.81 g  0.13 oz  0.01 lbs  0.79 tsp  0.26 tbsp 3.27 g  0.12 oz  0.01 lbs  0.73 tsp  0.24 tbsp 1.74 g  0.06 oz  0 lbs  0.44 tsp  0.15 tbsp 362.88 g  12.8 oz  0.8 lbs  TF = N/A

Note: No bowl residue compensation
Note that the combined weights for the two offspring dough balls comes to 17.98 ounces.
Next, I added the ingredients for the two offspring dough balls together and recalculated the baker's percents to get the combined formulation, again with no bowl residue compensation. This yielded the following final combined offspring dough formulation, along with the calculated thickness factor:
Combined Detroit and Boardwark Offspring Dough FormulationFlour (100%): Water (65.5836%): IDY (0.55537%): Kosher Salt (1.75%): Oil (1.08746%): Sugar (0.57864%): Total (169.55507%):
 300.7 g  10.61 oz  0.66 lbs 197.21 g  6.96 oz  0.43 lbs 1.67 g  0.06 oz  0 lbs  0.55 tsp  0.18 tbsp 5.26 g  0.19 oz  0.01 lbs  1.1 tsp  0.37 tbsp 3.27 g  0.12 oz  0.01 lbs  0.73 tsp  0.24 tbsp 1.74 g  0.06 oz  0 lbs  0.44 tsp  0.15 tbsp 509.85 g  17.98 oz  1.12 lbs  TF = N/A

Note: The combined offspring dough (17.98 ounces) is for a single 17.5" pizza; the corresponding thickness factor is 17.98/(3.14159 x 8.75 x 8.75) = 0.0747522; no bowl residue compensation
As you can see, the combined offspring dough formulation has an above average hydration value, a fair amount of yeast, and yields quite a thin crust. The oil and sugar levels are quite normal. Overall, on paper, the formulation looks to be like a NY style dough formulation but with an above average hydration value and a somewhat smaller thickness factor. So it will be interesting to see what results you get using the combined offspring dough. What will also be of interest is to see if the two different dough preparation and dough management methods you use for the Detroit and Boardwalk doughs are material differences that are reflected in the final results, especially since it appears that the fermentations periods are about the same from what I recall you said.
Peter