Get on KEH etc, or scour local stores. For film and meduim format there are times you need more light than your average flash can punch.
I have heard of people having good luck with Metz 45CT's.
I am not literate enough with the old analog sca parts to know exactly what works for ttl.
The 45 has a good flash sensor in the handle, or break free of the need for ttl or auto flash at all, and get a separate flash meter, perhaps integrated into a continuous light meter.
Once you move into more than one head at a time for a picture, you will end up needing a flash meter to interpret the resultant lighting ratios.
I for punch with medium format for on location portrature use three pack and head flashes supported on light stands. All of which are rated greater than 60 in metres with 100 iso film. It lets me use 100iso indoors and use f/8 or smaller for a bit of depth of field. Meduim format is shalow on DOF if you have just transitioned from digital or 35mm.
I have a md 70's metz 60CT2, running from a CT1 pack, with a mecamat sensor to allow its out manual output to be dialed down. I beleive newer CT's integrate this mecamat functionality into the head.
I have a Braun Hobby EF300 which is a mid 60's unit that can work at full or half power.
I have a Norman 200B , from mid 70's I guess, which can work at full, half or quarter.
I feed all of them AGM batteries meant for UPS's etc rather than expensive OEM batteries.