What is recommended practice for creating arrays of structured data?

define 'not going to be especially fast'. In this particular case I'll have 10 second sampling interval

It'd be perfect. You'll hit trouble if you try 100s a second, but for that it's fine :)

If your object is simple, just using DataView does makes a lot of sense. DataView itself is based on the standard JS one so we're stuck without any kind of increment - you could always add your own functionality I guess:

DataView.prototype.setUint16i = function(v) {
  this.setUint16(this.idx,v);
  this.idx+=2;
};

var buf = new ArrayBuffer(15);
var d = new DataView(buf);
d.idx = 0;
d.setUint16i(1);
d.setUint16i(2);
d.setUint16i(3);

While you can modify byteOffset in Espruino, you can't in normal JS so I'd avoid doing that if possible :)