Hey there,
well the 19 mm is the most versatile and comfortable strings spacing, especially if you like to pluck the strings even on D, A or E than just the G.
I know some fellas doing pretty good on that strings spacing, at the end it's just a personal approach.
The things is that is more easy to get used play on 16-17-18 five strings spacing if you start from the begin on that measure that if you switch from a wide or regular 5's.
And the most important thing is that the bass with the small spacing need to be your main instrument, it's the only way to get used to play it good and fast as a wide bass.
But, if you're planning to play back and forth from plus-strings basses, with a different spacing, it will be hard to be able to play the smallest one in the way you think.
For me 19 is the must, I can't even play like I want on 18 or 18.5 spacing, because I already feel the difference on my hands, but as I told you it's just my personal approach on the bass, as everyone has.
Play on smallest strings spacing bass, especially particular things, require time and practice, but nothing it's impossible.
Good luck.
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