Of course you'll save time and money when you produce all videos in a whole batch.
But what about the result? Are you really sure the final product will be accepted by the market? If not, you risk losing big part of the investment.
I think the lean practice should also be applied here in your case.
How about release one or several videos to the public or your old readers for free? Just to see their response to judge if your video will be hot. Also you could gain some initial popularity if the free one is good.
Hope this helps.