Hi Argentum
Every serious peer reviewed study I've ever read has concluded that dextrins contribute little if anything to mouthfeel. Here is but one of them:
https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1989.tb04650.x
... "every peer reviewed study" you say, but then the very one you chose to cite doesn't say that
... it says (with my highlights, for emphasis) ...
In carbonated beer, the amount of dextrins needed to produce an increase in viscosity detectable by judges was 52 g/litre, which raised the viscosity by 0.31 cP as measured by capillary viscometry. Since beer usually contains between 10 and 50 g/litre of dextrins, it is concluded that dextrins are not the sole determinant of beer viscosity.
... there's a bit of a leap from "not the
sole determinant" (implying that it is a determinant, just not the
only one) to "contribute little if anything", isn't there
... and that 52 g/litre, relating to viscosity of 0.31 cP, isn't an absolute either, as that paper goes on to point out, the threshold for increases in viscosity/mouthfeel drops to 0.10 cP for decarbonated beer. I'm quite sure I've read elsewhere that that's not a step function, and the perception of viscosity/mouthfeel will increase as carbonation decreases (and temperature increases).
Now, I don't want to come across all xenophobic ... all "Bloody Americans, coming over here trying to tell us how to make beer ... we've been making beer since before they could spell 'declaration of inderpandance'."
... but you do need to recognise that we're not all in Ohio on this forum and Nige did explicitly state he was using this in "bitter or strong barleywine types" of beer ... styles which are likely to have been brewed fairly dextrin rich, in the first place, and then he's adding more malto-dextrin into them ... they're also styles which are likely to be served less highly carbonated and warmer than many other styles (and served less highly carbonated and warmer here in the UK than where you are
) ... do you see where I'm going yet? The conclusion of that paper isn't "dextrins contribute little if anything to mouthfeel", it's telling us that there are thresholds we have to get to before we can sense their impact, but the thresholds are lower for (different types of) beers, served in particular ways.
Cheers, PhilB