Remember that 8 bits PICs are optimized for unsigned BYTES so you should apply these rules:

• Use BYTE variables unless you really need a bigger size.
• Use WORD variables unless you really need signed integers. Signed integers cost is greater than unsigned integers, both in code size and execution time.

PMP booleans are BIT variables and they are very effective, so use booleans for all logical operations.
Boolean arrays are also supported by PMP, but very code and time consuming. Use them only for big arrays if you cannot do otherwise.

Finally, remember that in non-strict mode PMP is doing implicit casts in expressions, without warning (unless there is a possible truncation), so be careful in using mixed size terms in expressions, it may be very code size and time consuming.