[Snap Dragon]

What is the average space to leave between strawbs when planting out?

And are they happier sitting up on a raised mound of earth?

[Trillium]

I space my new plantings about a foot (30cm) apart so that they can eventually start their runners in the immediate area.
As for planting in mounds, if you think summer will be wet, or you've got heavy wet soil, mounded soil is perfect. It's freer draining and won't rot the roots. If it's a dry summer and you've put them into mounded beds, mulch well with straw to keep in moisture and keep berries clean.