Can I change the TPX VSAM files to use SPANNED records rather than NONSPANNED?
No. TPX code does not support SPANNED records. The VSAM files must be defined with NONSPANNED records.
However, the TPX VSAM files can be defined with a bigger maximum record size if you are getting error 'MENG0004 VSAM access error. RTNCD=8, REASON=108'. (See KD What does 'MENG0004 VSAM access error. RTNCD=8, REASON=108' mean when trying to save a table in TPXADMIN?)
IDCAMS: RECORDSIZE(avg max) (Abbreviation=RECSZ) - supplies the average and maximum record size for a cluster being defined or altered.