If you are testing to determine best mix ratio, vary your cement input from 10% to 5% by halving the distance between the 'earth' and the cement lines.
Kama unapima kupata mchanganyiko mzuri, badilisha kiwango cha saruji toka asilimia 10 mpaka asilimia 5 kwa kufanya nusu umbali wa mistari ya saruji na udongo.