Steve,
One of the thing that I do as soon as I have a new pneumatic is to remove the safety for all of my guns, that way you never will have the same problem again. The other one is change the original shaft. There are some tricks to improve the performance of the gun without putting a Mamba but you need to open the gun and make a little work inside and change the oil.
Regarding the line releasing problem, I saw in the pictures that you do not use a reel, well put a little rubber bungee in the muzzle and then attach the mono there, this will mantain the rigth pressure in the line when the gun is loaded and you will not have more problems.
Do you have an idea of what pressure are inside your gun?
That will be really useful if you have plans to upgrade the gun with a Mamba kit, That way you will be able to compare the pereformance at the same pressure.
I understand that you will not change the bands guns for clear water, because you have excellent bandguns.
Who made this guns for you? jejejeje
Cheers
Ivan