Great explanation for your reasons!

One thing I would like to emphasize, as I see you're voting heavily for the top 20:
Anyone in this group receives the same share of blocks, no matter which position they're in. A vote for someone far up there is practically lost. It helps securing the chain in case of a takeover attempt, but when you're active you can change it anytime should it be necessary.

The guys further down the list are actually a lot more dependent on your votes. The so-called "backup witnesses" get to produce blocks depending on the amount of votes they have. By voting for someone in the lower ranks you actually have an influence to support the work of newer or generally less established witnesses, and as long as changing the vote from one of the top doesn't move someone in or out of the top 20 nobody loses anything.

It's also not necessary to use all 30 votes. Take your time to know who you're voting for, it's better to have a few spare than just voting to fill the number.