Not sure I would always immediately trim for best glide.
At say FL150 I have something like 20 mins of glide at Vbg, but anywhere more than 20-odd nm from land I will ditch anyway (assuming nil wind) so I would immediately
pull alternate air (fuel injected engine, note)
fuel pump on
change tanks
and then trim for Vbg (95kt).
One can do the above 3 within a few seconds; the speed will barely have time to decay, so trimming for Vbg will be pointless.
The only time I would go for a landing without trying anything else first is in case of an obvious catastrophic mechanical failure: a big bang and the prop flies off, or the prop suddenly stops, or I see a conrod sticking up through the cowling, or there is massive vibration (e.g. a blade gone partially or wholly missing) and I have to shut off fast.