The thing that took awhile was writing the program to do it. The steps are mathematically simple. It's just you're doing it on a large scale with 100 ridings in each region, roughly. That's not the difficulty. The thing that you would have to wait for is for all the votes to come in, because under this system each vote would count and each vote would matter, and you would actually need to know every last vote before you could determine the final outcome.
On election night, for example, when you watch the news, what they would be able to tell you first is who wins the first seat, as they do now, and based on the regional voting results, they'd be able to tell you what the composition of the House of Commons would be. But they would have to wait until every last vote is cast to determine who those second MPs would be.