Horses for courses but ....
I considered doing my cpl in a twin, but decided against it. A couple of people at my school did it in a twin (one did ok and one struggled) but I am pleased I did the cpl in a single.
Don't under-estimate the step up to a twin from a single. It's not massive but it is significant and don't under estimate the cpl skills test, it's not a stroll in the park. So why make if more difficult for yourself?
You have plenty of time to get familiar with the twin during the ME and IR and all the IR sim time you will have.