Steve and aquaxel gave you both really good info and prevents!!!
Just Adding closed liftbags if possible, really much safer to work with!
No deflation, and much easier to tow!
In case of emergency during back trip, Try to not exeed primary depth
A longest way back could be more safe!
And working step bay step at 5 meters is also much easier and safe to manage wreck, air needed for liftbags!
Just keep in mind when the boat will be close to surface to not avoid the marking boye, let it in place to prevent another lost!
cheers
Bernard