I've been a Sr. Rigger for just over a year now. In that time, I've had a couple clients ask me to make modifications to make their old gear (Talon 1 and Vector 2) more free fly friendly.
In both cases, I consulted with the manufacturers who said there are no approved modifications to make the gear more free fly friendly and that the jumper should get gear that was engineered with those purposes in mind.
Still being a little wet behind the ears, I'm sticking with what the manufacturers are saying and declining to make the requested mods. I've passed that information on to my clients and suggested they talk to a master rigger if they want to get more information.
I'm wondering what you experienced master riggers would tell them if they were to contact you. In both cases, it was an issue with the reserve flap coming open while sit flying. In one case the reserve pin popped at the same time the main was deployed resulting in a 2-out. He landed the biplane off field without injury. I have no idea if the 2-out was actually caused by the loose reserve flap, but I'm sure it didn't help.