Cello practice
1. Vibrato in time with fast beat
2. Scales with beat as fast as possible, focus in particular on second position, extended position, etc.
3. dotzauer book with and without fast beat
4. some time spent without a beat just enjoying playing
5. various pieces with beat as can manage

Viola practice
vibrato exercises with beat, especially c string
then if I have anything left to continue to hold proper position, a bit of time just playing whatever