I received 2 beautiful Thonet S 411 armchairs, which I want to have renovated by a professional upholsterer. But it seems that upholsterers have different opinions on how to deal with chairs' metal coil springs.
Opinion 1: Keep the springs only if the original ones are in good condition, otherwise remove them completely and put only foam in the chair.
Opinion 2: Keep the original springs if they are in good condition. If they are in unsatisfactory condition, replace them with new ones.
Opinion 3: Definitely remove the springs and use foam as a replacement material. It will be cheaper and more convenient. Original springs are not comfortable and most likely in bad shape and replacing them with new ones will decrease historical value anyway.
So we have a dilemma. The armchairs are not just collector's items and we want to use them everyday in our home, so they should be comfortable. But we also want the chairs to retain their historical value as much as possible. How would you approach the problem? Thanks for every opinion.