(Tl;dr – I like bar-ends a lot, but found SQlabs innerbarends unfit for my hands and purpose/s)
I once tried the SQlabs innerbarends and they lasted one ride.
Reasons:
1. Annoyingly small in both diameter and length (even with my tiny T-Rex digits)
2. Made the bar feel too short and so felt only semi-useful as a ‘rest’ on very straight sections.
As a rule of thumb (!swidt?) subtract about 350mm off the length of your bars ie
135mm x 2 (grips)
+
30mm x 2 (controls clamps)
= 330mm (plus any extra to clear your outer palm from controls clamps)
For comparison – my regular retro drop bars put brake hoods at around 420mm apart, which I find to be too narrow (for my lurch-like shoulders)
innerbarends on a 780mm bar will sit at around 410mm. Incidentally this has put me off splashing out on KOGA Denham bars as their inboard bar-ends sit at 400mm.
That’s enough about inners.
Bar-ends in general (ie installed at the end) though
I’m big bar-end fan in both senses of the word and since 1990ish have tried a fair few. Value of them for me is mostly for a wrist-rest, a little back stretch, and their indispensability for accelerating, honking/climbing.
Funnily enough I just installed some Ergon GP3s (basically narrowish stubbies)via a narrow flat bar on the tourer, and was yesterday comparing their function to the prior road/drop bars.
They give more power/purchase/leverage on (wider) flat bars of course. It’s quite startling how much acceleration and power is available once your thumbs are pointing upwards at 45deg as opposed to them being curled under a grip. My muscle groups are happy. They offer more power than I get from the hoods also as I can make a full fist around a bar-end.
Obviously bar-ends forego that ability for speed-scrubbing/emergency braking offered by drops/hoods (hoods = bar-ends for roadies 🙂), yet this isn’t generally an issue during standing starts, climbs or clear, boring flat sections (optional headwind) – ie three situations where bar-ends shine on MTBs/ATBs/hybrids etc