Team B Advice Appreciated

D5 Pro, BDE 5.11, PDOX tables

I have an app running in p-to-p environment with only two pc's sharing the
data. The 2nd machine runs very slowly when the first is running queries (I
suspect the update queries as they use the whole data set and not a filtered
subset). Sometimes a button will remain pressed for up to 30 seconds on the
2nd machine before the event is fired. I am not overly worried about
transactions (maybe I should be) as the two systems never work on the same
record at the same time. Big question: Should I be allowing cached updates
and applying cached updates. I have read tons of stuff but no direction is
clear enough. If I start using cached updates should I use them on every
table or just the busy ones? What is the rule of thumb? No app should run as
slow as this one does. Both machines are win98, 500MHz, 128MB, 10mbps