To hyphen or not to hyphen: that is the grammar question of the day

[Squigean]

What do you do if you have a choice of what would be compound modifier. For example, is it:

You have a choice of a one, three or five-day course.

or

You have a choice of a one-, three- or five-day course.

I can't figure it out!

Technically, the second one is right, but most style guides say the first way is acceptable too.

I would avoid the need to hyphen and change it to:

You have a choice of courses lasting one, three, or five days.

The latter, all the way