Prime Dose Use feedback?

I’ve been brewing for a couple of years and recently started doing some big beers (barley wine 12.31% and RIS 11.00%).  With that being said I over looked the need to pitch additional yeast with my priming sugar.  Needless to say when I went to try them there was no carbonation.  I have read some good reviews about prime dose capsules for this exact purpose.  my questions is should I use less then the recommended amount since there is unconsumed sugar from when I bottled.  I know I can experiment with different amounts of capsules but I was wondering if anyone has any real life experience with this.  I did them as 2.5 gallon batches and would hate to experiment with four of bottles.  I would hate to see there great tasting (flat) beers turn into gushers.

no experience here but I would consider just using fresh yeast instead of the prime dose if there is already sugar present. I like champagne yeast for this purpose as it will not ferment any of the residual sugars the primary yeast left behind but it is alcohol and pH tolerant.

A couple grains in each bottle dosed with a tweezers, or re-hydrated and dosed with a syringe.

here is a link to a previous review:

https://www.homebrewersassociation.org/forum/index.php?topic=21427.0