Except for the fact that, by introducing your 'foreign' VQs you'll effectively be helping to dilute the characteristics of the local drone pool, given that the male progeny of those VQs will comprise solely imported genetic material.
Double edged sword, I guess. Over the years, I have had many goes at bringing different strains into my apiary, to try and 'improve genetic diversity' and promote 'hybrid vigour'.
Experience has led me to conclude that's just a total waste of time and money for a hobbyist like me. Bee characteristics were patchy.
Now I just keep 'local' bees, and all is good and stable.
Given the length of time bees have thrived on these isles, nearby DCAs must already be serving up sufficient diversity (plus, locally adapted genetics).
Unless you're in the business of attaining the 'perfect bee' or chasing huge honey yields, I now don't see the point. In fact, my two best honey harvests have come since I stopped t*tiing around with buying in Q's, but have instead focused on the health of the bees I have.
Good luck with your trials! I'll be keeping an eye out for the results of your local matings of those brought-in Queens.