No, it is not acceptable and it is never done. It used to be done before the changes that appeared gradually in the 15th century, inspired by a paper most likely written by Jan Hus around 1400.
Before that the orthography did indeed use these digraphs, although somewhat differently.
cz meant c, not č
chz meant č
zz meant s
ss meant š
in the older form. It was not unified and it changed over time.
In the younger form
cz could mean either c or č
s could mean either s or š
ss could mean either s or š
They give this example from Alexandreis:
Knyez Allexander wtu dobu - Kněz Alexander v tu dobu
ſpade v weliku ſyrobu - spade v velikú sirobu.
Otczyka yuz neymyegeſye - Otčíka juž nejmějéše,
matky také newydyeſie - matky také nevidieše…
If you try to use these for modern Czech it will be completely unusual and very difficult to understand to most native speakers. It is never used.
What Czechs do very frequently instead is to just omit the diacritic marks and just use the basic letters (c instead of č, s instead of s, a instead of á, i instead í,...). It is very common in text messages and e-mail. Even at work.
One just writes:
Cau, mohl bys prosim odpovedet...
Čau, mohl bys prosím odpovědět...