@jcstander Hey, I'm new to this and mining since two or three days with a bit more of 1TiB (but a lot more is already ordered). Your image looks good. You don't have any DLs yet, because your chosen pool might have quite low Deadline threshold. The deadline (DL) is merely a random value somehow generated from the nonces of your plots. The mental model I use is like this: the network sends a new block (question) and the miner searches his plots for an answer. This answer is expressed as DL in seconds. Depending on the pool your answers are accepted, or not, i.e. the lower the DL the more probable is the acceptance. There are some pools out there that may accept any DL, but most of them set a threshold, e.g. 14 days or whatsoever. So, according to this your screenshot indicates that you rarely undergo the threshold. The chances for lower DLs (should) raise(s) with more space...To have an idea: I recently got a 19hours DL, which is one of my lowest DLs I reached so far. My pool (burstcoin.de) seems to have a DL limit around 14 days. Once I upgraded my system (first step would be around 5TiB) I expect lower DLs more frequently
Regarding the Read Times: I have a small plot (250GiB) on my Evo960 SSD, which performs with approx. 170 MiB/s and another ordinary 1TiB HDD connected via USB3, which performs between about 60 to 70 MiB/s. I see no huge difference on finding "answers" between both...the response time of my SSD is obviously superior. I'm not sure what connection you use for your drives, but 30 MiB/s is not really outstanding (USB2 or SATA II?), but not that bad. Your response times are about 3 secs, which seems ok to me. But the larger the plots are the more time you'll need to scan it. You might think of buy an extra card like PCIe to SATA III/USB3 (https://www.amazon.com/Inateck-Express-Connector-Controller-Internal/dp/B00FPIMJEW)...
As I said, I'm new to all of this, too...the more experienced guys here, may have better tips on this...