I haven’t validated the calculations for accuracy, but quick scan of the numbers look good for this calculator. One of my friends sent it: http://www.acoustic.ua/forms/calculator4.en.html
You may want to experiment with position in and around the calculated values. Some ideas below on holding the panels in place for listening tests.
If you want to go cheap, I have used something like this to hold things against the ceiling when I don’t have helping hands, or I don’t want someone standing in the way of the sound. The trick is to fully extend it just slightly off vertical (so it is slightly longer than the distance to the floor), lock it, then push the base towards vertical so it has enough pressure hold whatever you are trying to hold in place. https://www.amazon.com/Mr-LongArm-3212-Pro-Pole-Extension/dp/B00004YUPO/ref=sr_1_8?keywords=extensio...
If you want to get a bit more sophisticated, https://www.amazon.com/FastCap-Support-System-144-Inches-3HAND5/dp/B000067S12/ref=sr_1_12?keywords=d... is even better. Well worth the $70 for a set of two. You can hold an acoustic panel in place with one on each corner.
You may want to experiment with position in and around the calculated values. Some ideas below on holding the panels in place for listening tests.
If you want to go cheap, I have used something like this to hold things against the ceiling when I don’t have helping hands, or I don’t want someone standing in the way of the sound. The trick is to fully extend it just slightly off vertical (so it is slightly longer than the distance to the floor), lock it, then push the base towards vertical so it has enough pressure hold whatever you are trying to hold in place. https://www.amazon.com/Mr-LongArm-3212-Pro-Pole-Extension/dp/B00004YUPO/ref=sr_1_8?keywords=extensio...
If you want to get a bit more sophisticated, https://www.amazon.com/FastCap-Support-System-144-Inches-3HAND5/dp/B000067S12/ref=sr_1_12?keywords=d... is even better. Well worth the $70 for a set of two. You can hold an acoustic panel in place with one on each corner.