Excellent choice by using a Vietnamese 1665 case as a base for reshaping
I only swear by Vietnamese cases for vintage builds
They have the right general proportions and thickness (especially for the 1675), and they all have the correct crown/stem/tube height (unlike the Cartel / BP vintage / JKF watches which are designed to house the 2836-2 @ 2.25mm stem height or the 21j)
Vietnamese cases might cost $800 each for a complete case set, but it saves me from headaches and paranoia from getting called imo
I wished there were more options between the price jump of a cartel/ BP vintage / JKF and a Vietnamese case. I could already confirm that a Helenarou 5513 case is very inferior to my Vietnamese 5513 case