Preparing Salmon en Croute in advance

Having not properly entertained since before the dreaded Covid, I am now going to try and produce a salmon en croute for 8 people. I have already cheated and purchased all butter puff pastry sheets. However, to minimise the anticipated stress and panic on the evening, how far in advance can I prepare and pop it in the fridge? As well as the salmon fillet I will be putting in spinach and cream cheese stuffing. It would be great to assemble everything an put it in the fridge well in advance but will it all go soggy?