Thanks for your replies. That is reassuring.
As a reminder to those on vdrums, this is my set up.
Module 1 &
2:
Drums
Top Left/Left Middle PD-8 Pads
Top Right/Right Middle PD-8 Pads
Bottom Left/Left Middle PD-8 Pads
Bottom Right/Right Middle PD-8 Pads
Cymbals
None
Module 3
Drums
Left 10×8/Right 12×9 Rack Tom
22x16 Bass Drum/16×16 Floor Tom with Legs
Cymbals
None
Module 4
Drums
14×5.5 Snare
Cymbals
Cowbell
10 inch Splash
14 inch Hi Hat (I think this has its own dedicated port on the module, does that mean I could save one of the ports for another trigger?)
Module 5
Drums
None
Cymbals
18 inch China
18 inch Crash
20 inch Ride
Total ports: 19 (1 or 2 spare)
20 ports over 5 eDRUMin modules
I wanted a way to conceal as much cabling and components as possible. Initially the idea was to add one module to accommodate the three toms and bass drum itself. That's three holes in and one hole out (four total).
Then I thought, why stop there? I can eliminate all the cable slack and keep everything tidy by having all/most of the modules inside (remember, I have five).
If Dave can make a splitter box for bell, bow and edge (same principle used by Yamaha apparently) then that frees up six module ports of the 12 I would have needed for all my cymbals and cowbell.
This frees up six of eight ports needed for the Roland PD8 pads to use them without splitters giving me back rim and enabling me to use them as triggers for claps, clicks, whistling and other sound effects. I originally got them to use as an alternative to creating electronic/silent rototoms as I love how they sound in Pink Floyd songs and couldn't figure out how to mount them all and also didn't want to use up so much space for something so specialist having read how many people bought them thinking they were cool and then never really used them.
All holes will use chrome hardware and placement will be optimal for keeping things tidy/concealed.
If slightly larger holes can be made, several cables can be fed through one hole. I think there will be several different sized port hole hardware sizes available.
I figure five cables can fit through one hole. That means
one hole for five USB cables (others could use a USB hub inside the bass drum meaning only one data cable coming out and four other inputs).
One hole to the left low down for five PD8 pads,
one hole to the right low down for three remaining pads (plus two cymbals including hi-hat and crash).
Four smaller individual
holes for the three toms and snare (likely using one of those holes for cowbell) placed optimally (two on top, one left mid height and one right mid height) so that when the drums are positioned the cables cross over where drums almost touch.
That's five data cables out one hole, eight pads and two cymbals in two holes, plus toms, snare and cowbell in four holes and one (or two) low down hole(s) depending on location of each cymbal for splash, china and ride. We don't have to worry about the bass drum itself, as that's where it will all be at anyway. Total of 9 holes for 19 inputs and could actually lose several of those holes (if combined more and had less drums).
A second cross bar would be needed to secure slack cabling with cable ties to eliminate any movement inside the bass drum.
I'll get back to Dave and see what he says.