I use a cheap and crappy setup I put together for about $1.99, it does the job though.
The main capture device is a VIDBOX HT USB DV Capture box. It only does composite or S-VIDEO, works okay with the Tandy 1000 (though I'd probably get best quality with a monitor attached)
The second capture device is what I use to convert my VGA Signal into a Composite signal, this is a "PC to VIDEO EZ" box. It works alright. I've also used to to run my VGA machines into an older CRT TV or a TV without VGA inputs.
I use Open Broadcaster Studio for capturing the footage, and I use OpenShot Video Editor to edit the video captured and piece it together for youtube.
The computer I'm using for all this is a Core 2 Duo 3.0 GHz with 6GB of RAM and Windows 10, with a 512GB SSD and a 1TB SATA HDD. I eventually plan to upgrade it sometime in the next year or so when I can afford a new CPU/MOBO/RAM setup for it in mATX format. It does the job but it has been a little more sluggish lately. There is also a little latency between what is actually on-screen on the PC being captured and what is on-screen on that actual device (if I'm not using the capture monitor on my main PC to see what I'm doing). It can't be too bad though - made it to Night 5 on FIve Nights at Freddy's using my old crappy Win7 Toshiba with this setup without dying once so the latency is a non-issue for 90% of what I'm doing.
Here's a a screenshot of my 486 DX4-100 running Windows For Workgroups 3.11 from just a few seconds ago
Plus I did a new trailer today showing some footage of the rig in action in short spurts