I've recently started playing Dota again (although not on my channel as of yet, need to improve first!) and am hovering around 2.6 - 3k MMR. Techies boils my proverbial! Hate playing against him.
I have to say though, I disagree with you about playing safe lane carries to raise MMR. If you play a hard carry like Magina or Medusa you're gonna need to farm a lot before you can have a presence on the map. In low MMR games people are gonna be dying and 5 man roaming so often that you probably won't get the farm you need. For my money, the easiest way up would be to get good at roaming Pudge. Utility from early game all the way through to late game, don't have to rely on last hits so much and your hooks can result in a lot of kills in low MMR due to poor enemy positioning / juking ability.
Also as Sven, in low MMR if you don't have someone stacking ancients / neutrals for you then in the late game you're gonna be missing that big timing window of gold Sven needs to be effective.
But hey, I'm not exactly the best Dota 2 player going so take what I say with a pinch of salt! Good video tho!