I'm a mac-user but I believe these optimization questions are agnostic. *System/Settings questionnaire complete below*, and THANKS! This is my favorite client to data and I'm happy to report andy bugs and assist with the dev however I can.

ISSUE: Not getting the same DL speeds as Transmission, and DL speeds in general jump around a lot. Upload in general is OK, though I've wanted to increase overall before leaving my old clients (Transmission, uT, Deluge). Based on advice I find on the net and my own knowledge/research, I've been playing with a few settings, but I'm not exactly sure what is helping or hindering.
Tonight I had 2 large multi-season show packs, so had plenty of time to compare, re-start, re-boot, and tweak settings.
DEVICES, ROUTER: My ISP's alleged package is 300mbps down and +/- 20mbps up, which I typically get or exceed wirelessly (R7000), but speediest.net data with apps/devices off/idle included. The devices on our home network (US-Cablle ISP to R7000 w/ 2 residents, Samsung SmartTV, Kodi box(SS), Roku (handful of extra channels/streams), and the few phones, tablets, etc.) But regardless of that, when I A:B test against transition, like tonight, I'm the only one home and all devices are idle or off. I have various ports forwarded, like for qBittorent, and also currently have UPnP enabled for the time being.
GOAL/DESIRE: Sorry for the wall of words, just hoping for some tips in the right direction re; optimization plan. I now have more settings than Mac: Transmission and uT and still learning what they all mean. I hope to determine why healthy torrents are jumping all over the place regarding speed at times, and hope to improve performance overall without hurting streaming from my other devices, ike Netflix, Amazon, Roku, the StreamSmart (on an isolated Guest Network).
FWIW: I'm mostly part of some private orgs, so need to keep disable DHT, PeX, Discovery (same settings as other A:B clients).
THANKS AGAIN!!!!
[My System & Settings]
Speedstest.net:
251.52 Mbps ( 31440 Kilobyte/sec) 80% = 201 Mbps, 25125 KB/sec
14.42 Mbps ( 1802.5 Kilobyte/sec) ) 80% = 11.5 Mbps = 1442 KB/sec
*Speed: Global Rate Limits:
Upload: 1150 KiB/s
Download: 20000 Kib/s
*OS&Version
Mac OS = 10.10.5 Yosemite
qBt OS = 3.2.4
*Connections
Listening port: 64444 (port forwarded, same port tested with other clients)
Upload slots: Global maximum and per torrent:
Global max connections: 1200 (has been from 200- 1500 in Transmission. I read that keeping it lower, like 500, is actually better(?))
Max per torrent: 250 (has been 100 - 150 in Transmission w/ fast downloads)
Global max upload slots: Unchecked
Max upload slots per torrent: 9
Half-open connection value: 5 currently (have tried 20, 50, unsure if any effect)
Is uTP on or off? ON
Rate limiting uTP?: ON, to ‘Transport Overhead’ only
*Torrent Queuing
Max active Downloads: 4
Max active Uploads: 4
Max Active Torrents: 5
Encryption on or off?: PREFER ENCRYPTION
IPv6 on or off?: OFF
Connection status? ONLINE (always)
DHT node count (on the status bar): N/A (DHT, PeX, Discovery = OFF)
Are you using a proxy or a VPN? NO
*A few Advanced settings I may have changed (and/or confused about):
Disk Write Cache: 512MB, 30 sec interval (I have 16GB Ram, SSD HD, 2.6GHz Intel i7)
Outgoing Ports: (Min): 0 (It was at 3 earlier, set back to 0)
Outgoing Ports: (Max): 0 (it was at 8 earlier, set back to 0)
Transfer List Refresh Interval: 1600ms (I may have accidentally changed this form default)
Resolve Peer Countries: ON
Maximum Half-Open Connections, 5 now (I don't understand what this even is(?))
Confirm Torrent Recheck: ON
*What type of user profile are you?
Do you seed more than download? I seed more than download
How many tasks do you expect to run on average? 1 – 5 downloads at once would be great, as many seeds uploading as possible (to build ratio at a few special places).
Do you use the machine for other tasks simultaneous with BitTorrent downloads: Yes, but very little is network or processor heavy afaik.
Are there other users on the LAN? 1 housemate with computer and phone (on different 2.4 GHZ band). Overall, a handful of devices like tablets, Xbox, PS3 ROKU, Samsung Smart TV (but al off during recent testing/optimizing), Android StreamSmart box, Roku private stream channels, Plex with same computer as server.
If a specific loaded task is a problem, please provide: Errors pop up sometimes and slowly rise a bit or go away. "qBt must be restarted' occasionally as well.
Seed and Peer counts in bracketed form x(n) ... The number in the bracket is possible, the number outside is actual.:
Torrent A: Seeds 13(13) Peers 0(1) (jumping around from 12-15 MiB/s to as low as 2-5)
Torrent B: Seeds 36(46) Peers 14(9) (" " ")
Again, thanks for any insight you may provide and I will keep an eye out for any issues I discover and report here.
Kind Regards