And what happens if I've done the claim process yet with min weight magnitude = 15?. Can I repeat changing this parameter, or will generate another new problem?.

I am very confused with all this. My old seed is totally incompatible with current format. It's short in lenght and has "1" to "8" digits . Not sure if must use short lenght, or must fill with 9's until 81 characters long.

And now, not sure if I must repeat all combinations above, including min weight magnitude=15. Not sure if can/must choose  a diferent NEW SEED for every claim...

I fear have done something wrong and now can't claim my IOTAS.