How precise in sync to Rosegarden+Hydrogen?

I like Hydrogen for drums, but I have other things I want to sequence - pads, keys, etc. Is the following workflow feasible/smart?

Sync Hydrogen to Ardour via jack.
Set both to 90BMP
Do the song’s drums in Hydrogen
Record Hydrogen Drums to a Region in Ardour
Close Hydrogen
Open Rosegarden, set to 90BPM
Rosegarden is synced to Ardour via Jack
Do the rest of my sequencing
Switch to Ardour to record audio tracks
Mix Down to a stereo track (to capture outboard synths)

I’m worried about things syncing up precisely. Will I be able to work with regions with snapping set to barlines in Ardour?

With jack transport the sync is sample accurate.

How do you “Sync Hydrogen to Ardour via jack”? Never done that . . .