I'll accept Greg's description of the video. My question really goes back to your original post. Why did you feel it necessary to use an EPDM sealant or any 'sealant' for that matter? Firestone makes a good EPDM sealant but normally if it is applied on vertical surfaces a term bar is required to maintain the integrity of the seal. On horizontal, tension free surfaces, it works quite well if applied correctly.
The use of this sealant should not have any bearing on your water loss unless you seamed Two separate sections of EPDM.
"Everybody is ignorant, only on different subjects." - Will Rogers