Proto4 board fully populated with all the Teensy-related headers:
A little closer view:
Thanks to free samples from Samtec... I've worked out the combination of mating headers necessary for the through-hole and SMT-mount headers to have the same mounted-height.
On the Teensy 3.x board:
1) All through-hole header strips: Standard size (~0.230" long pin above 0.100" thick insulator). The strip should be inserted on the bottom side then soldered on top.
2) The SMT-mount headers should be Samtec P/N TSM-1xx-01-T-DV (or gold, -G-DV).
On the Proto4 base board:
3) All socket-header strips for the Teensy's "standard" header strips: standard socket-strips with an insulator height of ~0.330".
4) All socket-header strip for the Teensy's "SMT-mount" header strips: Samtec P/N SLW-150-01-T-D.
With this combination of headers, the mated PCB spacing (between the Teensy and Proto4 board) will be ~0.430".
What a rip-off...
Of course, when I was trying to figure out the right combination of headers/sockets I had initially selected the wrong length header-pin for the Teensy's SMT pads. Argh! I should have done a little math before soldering them on to the SMT pads on the Teensy.
After Samtec sent me the correct parts - the challenge was then to carefully remove the SMT-headers and replace with the new ones. Not easy... I ended up ripping some pads off the Teensy board:
This is not a new problem... I've read elsewhere that this isn't an unusual result. Either from de-soldering, or even just trying to unplug a "fully headerized" Teensy (you have to be realllly careful prying it loose). I'm sure there is a good technique for de-soldering these headers without damaging the pads - but in the 15 minutes I spent on this task, I didn't figure it out. I can still use this Teensy, just not the SMT I/O pins.
Summary: Everything seems to fit nicely. Next step? A Teensy-blinky project? I really don't have a need for this DIN-uino Proto4 board right now (today), but very soon... I'm sure it will become quite handy.
16-Sep-2017: The first board is mostly built, see gallery.
The SMPS (5V) and LDO (3.3V) power rails are solid. The internal power/gnd planes are NOT shorted (thankfully!).
Now I just need to sort out one little point of confusion: what are the appropriate SMT (bottom side) and TH (all others) header combinations to use on the Teensy, so you can plug it in and everything mates up properly. All the holes on the proto-board are in the right spots, that's not the problem. It's the combined "board stacking height" with different combinations of SMT and TH headers that is a tiny problem. Off by 0.1". I think I have the answer... but if anyone has good advice, please share.
11-Sep-2017: Boards have arrived! So far they look very good. Parts have arrived too... so the next step is to slam together the SMPS section and confirm it's working properly.
3-Sep-2017: Found a few more tweaks, I'm done. You know how it is - whenever I see blank PCB space - I want to put something there! If I don't send it off now - I'll be sure to find more changes to make. Final version front & back renders posted in gallery.
*** Sent out for fab today! Should have some nice boards in a couple of weeks or less.
31-Aug-2017: I think I'm finally finished tweaking the layout. Just about ready to send off for initial fab.