Well it's all about liability. There have been enough scare stories in the papers and studies of infant mortality statistics that the "experts" have said no co-sleeping. What they don't point out is that many of these overlaying deaths happened with drugged out moms, or sleeping on couches, waterbeds or poorly fitted mattresses pushed up against walls. I'm not saying that overlaying is impossible under the best circumstances, but I think there are people doing this who have no business sleeping with a baby. Even experienced co-sleeping moms shouldn't co-sleep at certain times - maybe you're extra tired or sick and have taken some cold medicine, etc... It's all about using discretion.
Remember, you're the mom. Get all the info and make an informed choice. The bassinette arrangement may still be the best option for you. Or, you might find daytime naps with the baby work good for you and you can practice. There's nothing that says you can't change the arragement as you go.