Hi. I just registered so I could ask some follow up questions. First is there a "system" behind the Lumia numbering? I would assume that the higher the number the better specs, but is there more to it?
First digit is market placement.
4xx, 5xx, 6xx, 7xx, 8xx, 9xx, 10xx, 13xx, 15xx, 25xx
4-6 are low-end models - generally cheaper, the lower the number, 7-8 and 13 are the midrange - 13 is the midrange phablet, 9, 10, 15 are the high end - 10 being camera-centric, 15 being the fancy phablet. The 2520 was a tablet, and in a class of its own.
Second digit is generation. (x0x, x1x phones were WP7 with one exception, x2x were initially WP8, x3x are WP8.1...)
The Lumia 510 was a Windows Phone 7.8 device.
The 520 was a Windows Phone 8.0 device.
The 530, 630 came after that and ran Windows Phone 8.1.
The 900 was the flagship for Windows Phone 7.
the 920's were the flagship series for the Windows Phone 8 run, partially superseded by the 1020, which brought the insane camera many have heard of.
The 710 ran 7.
The 720 ran 8. (upgradeable though, but still an older model)
The 730 (and variants) runs 8.1
Third digit is what variant of the model.
The 920 was the core high-end, last generation model. It spawned two variants, the 925 and 928. the 925 had a different set of compromises, including metal and whatnot. The 928 was exclusive to Verizon Wireless in the US.
The 520 was the core model for the premier budget phone of 2013 or so. The 521 was a variant made for T-Mobile US. The 525 was the same as the 520, except its RAM was doubled to 1 GB.
The 820 was the core mid-range model just under the 920.
It had the 822, which was the VZW exclusive, and the 810, which was the sole exception to the generation number. And exclusive to T-Mobile.
The 825 was a developer model I believe.
The 630 and 635 are core models, the former being 3G and dual-SIM, the latter being single-SIM and supporting LTE.
The variant duo, originally in China, the 636 and 638 are about the same, except for being upgraded to 1 GB of RAM, much like the 525 was, compared to the 520.
730 has dual-SIM, 735 doesn't and has LTE.
Regarding Tasker, there is some possible workarounds, but nothing to that extent, which is a shame I believe, but understandable since apps don't have direct access to system settings.