...
Parachute sizing was found using the drag force equation at the bottom left corner of figure 6. Putting in average assumed values resulted into a previously made spreadsheet calculator resulted in a total diameter of roughly 8 feet and a reefed diameter of roughly 3 feet.
Figure 6 Spreadsheet calculator and values used
...
Using the values in the spreadsheet, the shock force was found on OSCalc as shown in figure 7. For the drogue opening at 30,000ft, the upper bound of force is calculated to be 30330.2 32 slugs*ft/s^2
Figure 7 OSCalc results
...