On camera, handle mount, or pack and head style?

Bounce with flash is dependant on the height of the ceiling/proximity of the rear or side wall. This will determine the power needs of the flash. Doubling the distance seems trivial, but doubling the power of light coming out of a flash to light a scene with a slow film, or desire to shoot the scene stopped down for more depth of field is not.

Most people think of flash in terms of guide number for the smaller fixed reflector units.

Most 4 aa cell powered units are about GN 35 max (100iso film, GN in metres).

Handle mount flash, of the Metz, Sunpack, etc line use 6-8 AA's and have GN up to 45.

Shoulder hung accumulator and battery pack and light camera mount head units usually have beefier batteries yet again, and can deliver up to 60 or a bit more.

After than you are heading into the realm of monoblock or pack and head studio flash units.

I would not get hung up about whether the flash can electronically integrate with the model of camera you have.

Use the flash's own light sensor for your first flash when used on camera or even off camera when you think about what the flash sensor sees versus what your camera is seeing.

When you move on to lighting a scene with more than one flash you can spend the moon for electronic wireless exposure control, or save your money by buying simpler flash units, and spend the savings on a flash meter. Money spent on a functional, but not necessarily the 'flashiest' flash meter is in my mind always fund well spent.