Thanks a lot guys,
@RDFTKV info shows 40 pins header is 8.5mm high…
@Electr1 datasheet pdf shows 40 pins header is 8.64mm (8.13 + 0.51 standoffs) high…
Difference is 0.14mm, that’s negligible !
I think I never do better measurement with my metal rule (1/10mm) !
I’ll go for a 8.5/8.6mm high 40 pins header, I think it’ll be no problem to find that on AliExpess 
…
Best regards Guys !
Add-on 20210113 :
Hello All ! …
Let’s Go !.. Found that on AliEx :
2x20 pins PCB 2.54mm female header
2x40 pins SMD 2.54mm male header (will cut it to fit 2x20 pins SMD Tone2Pro port)
Just have to wait some days/weeks for shipping delay…
I’ll be back to you all when VIM3 + Tone2Pro mod. will be ready…
Should be the same as my DIY Case tuned Housing VIM2 + VTV + TONE-BOARD
Add-on 20211107 :
Hello All !
I dig up this topic because my second homebrewed board-sandwich VIM3+Tone2 Pro assembly is done.
If you are interested about it, juste take a glance to the first of the 3 phases I’ve posted here…