The decimal value 99 requires 7 bits so most you can save by packing values is 1 bit per value with the added overhead and complexity of unpacking them.

If these values are to be in RAM (which I believe is the case since you mention an array) then I'd say it's not worth the effort but if the values aren't changing and are to be held in "ROM" then, as it happens, the low end PICs have a program memory word size of 14 bits so you could put two 7-bits values into one program memory word.

/Henrik.