I would anticipate the related constraint to be the 1000 witness stack merchandise restrict for P2TR inputs. This could allow a script specifying at most 999 public keys in an OP_CHECKSIG(ADD)-based building (i.e. <key1> CHECKSIG <key2> CHECKSIGADD <key3> CHECKSIGADD <key_N> CHECKSIGADD <okay> NUMEQUAL), since every public key would must be paired both with a signature or an empty aspect on the stack. Because the script is executed, every public key would get pushed onto the stack and popped off with a signature or empty aspect by the OP_CHECKSIG(ADD). This non permanent addition of the general public key would trigger the non permanent one thousandth aspect.

That is from the highest of my head, I is likely to be forgetting one thing and it is likely to be a pair fewer in apply, however the magnitude ought to be roughly proper.

Should you have been to make use of the FROST scheme to create an aggregated public key and fulfill that with an aggregated threshold signature, your quorum ought to theoretically be limitless.

The PSBT would then merely be submitted as soon as a enough variety of signatures have been added. Both strategy would most likely be a horrible expertise in apply since coordinating the big variety of signers could be a headache.