Some Visuals for the 'Who to Buddy' Question
If one of your goals is to generate several high-CP defenders through walking (leaving aside defensive quality), consider these charts. For convenience, they assume a 100% IV hatch (thus Level 20) and plot the necessary dust (in blue) and number of km's to walk (in red) for evolving/powering up to reach at least 2800CP (on left) and 3100CP (on right).
The charts assume no other sources of candy besides walking - again for convenience, but also because even Rhyhorn and Magikarp are uncommon where I live. Of course, if any of these candies are over-abundant for you, ignore the km walked chart for them. You wouldn't want to buddy those mons anyway.
The charts also assume a 100% Level 20 hatch because it's a convenient baseline for quick visual comparison. The charts would still look similar for 87% IV, 82% IV, etc.
Here's what I'm seeing in the charts: If your aim is to get several 2800+ defenders through walking, Snorlax and Rhydon seem good unless you are particularly low on dust or mons. You can bring ten Snorlaxes (or Rhydons) above 2800 by walking before powering four Dragonites above that number.
If your aim is to get several 3100+ defenders, Tyranitar and Dragonite are good, especially if you're low on dust, but Gyarados is good if you're willing to pay twice the dust in exchange for half as much walking (and you're at least Level 35).
Which brings me to the last thing about the chart, added with obvious haste at the end: certain trainer levels are required for certain power ups. Necessary trainer levels are indicated in the middle of the dust chart.
It also seems smart to keep walking if necessary for any Dragonites and Tyranitars to get the boost from 2800 to 3100 (and Gyaradoses if dust isn't an issue), but it's a much longer walk to give Blissey that bump.
Anything interesting jumping out at you as you look at these charts?
Answers
It seems a good choice if you're relatively comfortable with defenders and expect to go up against more Blisseys and Tyranitars soon.
Check for good nests near you though, especially since they just changed. I rarely see Machops and finally had enough candies to evolve my first Machamp right before Gen2. This past week, however, I lucked out with a great Machop nest nearby. I spent a total of four hours there (over the past three days), caught 95 Machops, and Pinap-ed my way to about 600 extra candies (or 1800km worth, which is more than I've walked with the game so far).
You should take into account the 1 in 3 chance to get a useable moveset. You can walk 375 km for one machamp, it can easily be more than 1000 for a fight-moveset-machamp.
This can take some month until success. I use dragonite for attacking blissey and walk chansey instead ov machamp. As every blissey moveset is useable, the efford of walking will pay off garanteed.
