Bedding plants

[Teej]

Hi - just a bit of advice please!
I'm rubbish with non-edibles as I just don't have the same interest in nurturing them!  However, this year I've decided to get a few hanging baskets sorted & also get some colour & interest on the edges of the raised beds around our drive.  I've got various plants on the go & just wondered about the spread of some of the types that I've never had before - Verbena, Centradenia, Diascia & Helichrysum.
What sort of coverage would 1 plant give?  Just so I don't end up cramming them in a space too small or having huge gaps everywhere.  I've got the usual Petunias, Impatiens, Lobelia etc but I've never grown the 4 mentioned above so I've no idea of their size/spread.
Help much appreicated.
Thanks very much. :)

[Teej]

[RSJK]

all at 10 to 12 inches apart from helichrysum  which should have about 18 inches between them

[Teej]

Fantastic -  means I can use up loads of space with them!  Thanks Richard.