uTorrent for Windows: 2.84 MB https://www.utorrent.com/downloads/win
picotorrent.exe: 3.98 MB https://github.com/picotorrent/picotorrent/releases
picotorrent also seems to come with a language pack while you download uTorrent's separately at 1.3 MB. Not that I think it matters.
Also, don't forget to include any ads or malware that might download with your next version of uTorrent: https://en.wikipedia.org/wiki/%CE%9CTorrent#Ads_and_malware
But it must be noted that Transmission doesn't support animated emojis.
I've found it to be best, not tried transmission on Android tho.
I still try to keep it slim, fast and clean in overall usage :)
* Layout management. There's no "easy" way of managing dialog layouts (letting controls expand/shrink on resize etc).
* Custom controls (e.g a tree-list-view) are clunky to write.
You can hit me up at the email in my profile if you want to discuss further!
We wrote a layout manager and it's under 400 lines with very liberal vertical spacing. There's really not much to it - just hook the container window and reshuffle the contents in response to WM_SIZING, WM_SIZE. Handle WM_GETMINMAXINFO too if needed.
Custom controls aren't that much harder, but they do require some work indeed. TreeView and ListView are _really_ well designed in terms of customization support. The documentation is a bit heavy, granted, but once you get a gist of NMCUSTOMDRAW phases it's all pretty trivial from there.