An option is to design 0.75u tailor-made blockers to go with a 60% case that will fit nicely with them.
Actually i want make 60% alu high profile case with 1 line diffuser in the middle, and i will add more top option for YAS62 blocker, 60% std, HHKB style, and WKL if needed)
I like high profile case.
The design sounds similar to many of the creation of Duck0113. Do you work for him?
But I heard some bad reviews about PCBs of his keyboards, for sure Leeku is among the best.
Please also think about the possibility to remove the 1 line diffuser layer in the middle.
There are already so many things to consider including forms and fit, and finish, etc. Just look at the 'simple' FJELL design, LeadreN told perhaps over a year working on it before having now the revision 4 prototype.
Looking forward to your design!