English for Writing Research Papers

particularly with regard to the weights of X, Y and Z.
 
S2.   *Owing to the difficulties in measuring the weight of the various compounds, particu-
larly with regard to the weights of X, Y and Z, it was found necessary to make some 
simplifications to our procedures, essentially by doing A, B and C.
In such cases, it might be clearer for the reader if you split the sentence into three 
(S3).
 
S3.   We encountered difficulties in measuring the weight of the various compounds, particu-
larly the weights of X, Y and Z. We thus decided to make some simplifications to our 
procedures. This entailed doing A, B and C.