> using an imported dog would seem a better option to me personally than going abroad.
trouble is it is expensive to get a top quality dog (much easier to use a top quality stud). The temptation is in a breed with small gene pool is for everyone to use the dog, and your back to square one in the next generation, and importantly the stud needs to be housed.
Many breeders keep only bitches (or can't accommodate more males than they already have), many of those who choose to own males don't breed, so can't justify the expense, especially as a dog in a small gene pool is never going to pay for itself in resulting stud fees.
I with 3 friends imported a male through quarantine 10 years ago, before Pet passports, he sired 8 litters mostly for the 4 of us in the partnership who brought him in. He is now in an awful large proportion of the dogs alive in the country today.
Just because a breed has large numbers does not always mean a large gene pool, your main breed has an average COI of 9.5% (that's double the COI in my breed) means that the average litters parents are more closely related than first cousins or half uncle to niece etc at 6.25%.
As this will include all the pet bred litters the COI's may actually be higher in various sub groups of the breed, eg show lines, working lines and BYB/PF litters.