Barrel Aging Liqueurs: with or without sweetener?

[Longleaf Distilling]

This may be a stupid question, but what is the guidance/tradition on barrel aging liqueurs? In all of my reading, I have never come across the subject and would like to store a few liqueurs in used barrels for finishing and bulk storage. More specifically, should the liqueurs be aged before dilution & sweetening or after? Does anyone have any experience with the comparative effects of both? 

For example, I could store a Nocino at 180PF and save a lot of volume, but I'm not sure how the barrel would react to that high of proof and concentrated walnut flavor. Alternatively, it could be diluted down to around 100 proof and sweetend before being stored. 

Any recommendations or advice? 

[Kindred Spirits]

I am sure people probably age both ways. 

The issues that arise with sweetened spirits in barrels is if there is a leak you have to deal with a sticky mess.  You also have to deal with the cleanup of the transfer into the barrels. 

I prefer to age then sweeten, that way you can more easily monitor your ABV and proof gallons barreled and collected.

The other thing to consider is that by putting it into barrels at high proof is that there will be some undesireable extractions of wood alcohols and other things that would most likely hurt your final product.

I would definitely recommend barreling closer to your final proof.

[Longleaf Distilling]

@Kindred Spirits Thanks for the advice. That’s what I’m leaning towards primarily for the proofing issue. I really don’t want to have to redistill a sample of every barrel to find the new proof.