How big they get depends on which one you have. If you have very finely cut, almost ferny leaves, it the native dicentra eximia which grows 10-18 inches. If you have the bolder foliage (with almost palmately-compound leaf), then you have the japanese dicentra spectabilis which grows 12-30 inches.

Yes, they like shade but will flower best if you make sure they get some morning sun.

Here is a link that might be useful: Dicentra differences

My bleeding hearts go dormant in the summer. Does anyone have a variety that doesn't?

The most common native species, Dicentra eximia and D. formosa, both often called "Fern-leaf Bleeding Heart, retain their foliage from early Spring until late Fall-Early Winter and are often grown as a foliage plant. But some cultivars, if grown in full sun or partial shade will produce blooms as long as the foliage persist.
Some of the named cultivars are readily available at most nurseries and box stores and range in color from white to dark pink(almost red). Growers Outlet has a pink one called 'Luxuriant'. Other pinks are 'Bountiful', 'Adrian Bloom', 'Stuart Boothman' and a couple with near red flowers; 'King of Hearts'(inter-specific hybrid) and 'Bacchanal'. White flowered cultivars: 'Alba', 'Snowdrift', 'Snowflakes', & 'Langtrees'
There are numerous other cultivars, but most aren't usually available in this country.
There is no agreement among nurserymen as to which species the various cultivars were derived from and some may be hybrids between 2 or more species.
Plant in sun or partial-shade, furnish ample moisture and enjoy!
Rb

Thanks.

Dicentra spectabilis looks great with Texas Bluebells in the spring or perhaps Iris reticulata or Siberian Squill for contrast.They usually all bloom together which is tough with Bleeding Hearts. The blooms on all are pretty short-lived.