I wouldn't necessarily double the flavoring percentages as it could cause flavor muting or, depending on the recipe, more of that chemical/extract flavor when too much is used (in any application such as cooking, baking, etc).
Increasing flavors could work, but I would do it in small percentages. maybe like 0.25% each, and see how that works. You could also try upping the sweeteners or adding a small amount of saline to give flavors more "pop" before upping the flavor percentages themselves.
Additionally, I had the same set up for a long time with the baby beast tank...and truthfully, with tanks I find I get more concentrated flavor out of smaller drip tips. Not only in the size, but also the material of said drip tip. For example, I have a GeekVape Peerless that came with a wide bore resin tip that I couldn't taste any flavor with no matter what, once I bbought a separate 510 (with a slightly longer length) I could taste juice much better.
You could also try adjusting the airflow as (with my personal tastes) warmer vapes tend to help you perceive stronger flavor.
The only other thing I could think of is the types of juice you're using. Since taste is subjective, different "genres" of juices could just be tastes more over others...for example, all custard juices taste exactly the same to me (most candy flavors as well) and I get burnt out on them very quickly. Where as with other bakery type flavors (which are my favorite) I tend to be able to pick out more detail in the recipes.
I'd also make sure you're steeping them for a while before you/your wife tests them out.