disk space analysis with OPNQRYF question

I want to build a file of containing the file sizes of each PF and each journal file on our AS/400.  To build this, I need to run DSPFD to an outfile for the PF's, and DSPOBJD to a different outfile for the *JRNRCV files.

Since I want only one pgm to process the outfile, I used OPNQRYF to make the DSPOBJD outfile look like the DSPFD file, and add the journal records to the end.

Is there a better way to do this?  I had to map many fields to blanks and zeros.  Isnt there a way to build a record format in OPNQRYF and use blanks and zeros to fill any fields missing in the input file?   This turns a simply OPNQRYF stmt into an ugly mess!

Any better ideas?  Thanks!

CL code:

            DSPFD      FILE(*ALL/*ALL) TYPE(*MBRLIST) +              
                         OUTPUT(*OUTFILE) OUTFILE(SUPPORTLIB/FDSKHSTW)
                                                                     
            CLOF DSPOBJDOUT                                          
            DSPOBJD    OBJ(*ALL/*ALL) OBJTYPE(*JRNRCV) +             
                         OUTPUT(*OUTFILE) OUTFILE(QTEMP/DSPOBJDOUT)  
            OVRDBF     FILE(DSPOBJDOUT) TOFILE(QTEMP/DSPOBJDOUT) +   
                         SHARE(*YES)                                 
            OPNQRYF    FILE((DSPOBJDOUT)) FORMAT(FDSKHSTW) +         
                         MAPFLD((MLFILE ODOBNM) (MLLIB ODLBNM) +     
                         (MLSIZE ODOBSZ) (MLCDAT '%SST(ODCDAT 5 2) + 
                         *cat %sst(odcdat 1 4)') (MLUDAT +           
                         '%SST(ODUDAT 5 2) *cat %sst(odUdat 1 4)') + 
                         (MLCHGD '%SST(ODLDAT 5 2) *cat +            
                         %sst(odLdat 1 4)') (MLMTXT ODOBTX) +        
                         (MLNAME '" "') (MLNRCD 0) (MLNDTR 0) +      
                         (MLRCEN '" "') (MLRDAT '" "') (MLRTIM '" +  
                         "') (MLFTYP '" "') (MLFILA '" "') (MLMXD +  
                         '" "') (MLFATR '" "') (MLSYSN '" "') +      
                         (MLASP 0) (MLRES '" "') (MLNOMB 0) (MLSEU + 
                          '" "') (MLCCEN '" "') (MLCHGC '" "') +
                          (MLCHGT '" "') (MLSEU2 '" "') (MLUCEN
                          "') (MLUCNT 0) (MLTCEN '" "') (MLTDAT
                          "') (MLSIZ2 0) (MLSTFR '" "'))       
             CPYFRMQRYF FROMOPNID(DSPOBJDOUT) TOFILE(FDSKHSTW) +
                          MBROPT(*ADD) FMTOPT(*MAP)            
                          CLOF DSPOBJDOUT                      
             CLOF DSPOBJDOUT                                   
                                                               
             CALL       PGM(pgma)     /* process PFsize records and journal size records.  */