Thanks for this quite complete report, Christian. Looks like you found a terrific setup! And you came up with a nice solution for the limited range of the Samplemodeling instruments. Reading your post made me look for my cheap Windows Bay Trail tablet and try out some SWAM instruments as well.
Of course, it's a 100€ 8-inch tablet (Dell Venue 8 Pro 3845, with 1G RAM), and Windows 10 is quite unreliable with it (I regret updating from 8.1), so I didn't expect it to be a trusty rig for live performance, but I found that it works surprisingly well for quick jams when loading only one VSTi.
First, I installed ASIO4ALL to be able to output low latency audio. Then, I downloaded the last 32-bit version of the SWAM Flutes and could install them without a hitch.
For the VST host, I didn't install Cantabile yet, but I had a copy of Hermann Seib's SAVIHost floating around (32-bit, VST2, with the embedded keyboard). It's a really bare-bones host with very few functions, but it does its job. So I copied savihost.exe to the same folder as the Alto Flute VSTi, renamed it SWAM Alto Flute 32bit.exe (the same name as the .dll) so that it would automatically open the VSTi at launch, and made a shortcut on my desktop. This way, I can just double-tap on the shortcut, and ten seconds later I can start jamming on the Sylphyo.
At first, I had some issues with some license dialogs on the SWAM interface that didn't manage touch input at all, so I used TouchMousePointer, an on-screen touchpad which is quite helpful when dealing with desktop and legacy software.
It was also helpful for precise pointing, so I could configure the virtual instrument with our recommended parameters without any problem. AFAIK SAVIHost doesn't allow to finely adjust MIDI input like you did, but a future Sylphyo update will allow to customize the ranges of CCs directly from the Sylphyo.
My tablet has only two ports : one micro-USB for charging and external devices, and one 3.5mm jack for audio output. Just enough for a battery-powered Sylphyo jam. So I connected the Sylphyo receiver device on the USB port using a micro USB OTG adapter.
In SAVIHost I went to the Devices > MIDI… menu, and selected Panda-Audio midiBeam as Input Port 1. Then, I went to Devices > Audio…, and I selected No Wave as Input Port, and ASIO: ASIO4ALL v2 as Output Port. After an intense parameter tweaking session, I settled on 44100 as the Sample Rate, and on 64 samples as the Buffer size.
To make it work without glitches, I also had to go to the ASIO4ALL control panel (in SAVIHost, there's a Devices > Asio Control Panel… menu), and change some parameters in Advanced options (the wrench icon):
set the ASIO Buffer Size to 64 samples
in the WDM Device List, select Intel SST Audio Wave for IHF, enable Out: 2x 48KHz, 16Bits and disable In: 2x 48KHz, 16 Bits
in the Latency compensation section, set both In and Out to 0 samples
and in the Options section, enable Allow Pull Mode, Always Resample, and Force WDM Driver to 16 Bit, and set Buffer Offset to 20 ms
With these settings, I could play without perceivable latency (there's slightly less when the output jack is used compared to the internal speakers).
SAVIHost shows my CPU is around 23% at rest, and around 75% when playing. I sometimes encounter brief buffer underruns (there are small audio glitches), but they should be entirely gone with a ≥128-sample buffer.
Having all the power of Samplemodeling instruments in such a small package is quite exciting! Here is a picture of my cheap mobile setup, and here is how it sounds. Again, for serious live performance I'd rather buy a powerful and reliable tablet like you did, but it's nice to know that even cheap tablets can run a Samplemodeling instrument.
The only issue I found with this setup is that there are much more glitches when the display is put to sleep, so I may have to create a custom "Sylphyo" power profile so that it never sleeps.
As for synth VSTs running on Windows, I rarely reach out for synths outside Live or other DAWs, so I couldn't say.