The first issue is that I don't think "efficiently" means what you think it means. From http://www.thefreedictionary.com
1. Acting directly to produce an effect: an efficient cause. See Synonyms at effective.
a. Acting or producing effectively with a minimum of waste, expense, or unnecessary effort.
b. Exhibiting a high ratio of output to input.
Since a LINKAGE SECTION merely describes a memory area being passed from another program, why would you think you need to minimize waste, expense, or unnecessary effort (1 and 2b of the definition don't apply in this case)?
The second issue is that the ONLY way you code a LINKAGE SECTION is to define the data being passed to the program -- period. There may be external restrictions (i.e., if you're passing a parameter from JCL you're limited to 100 characters) but you should not be concerned with anything except how the data fields are defined in the LINKAGE SECTION.