Ignore Mr. Malty. Per Wyeast 1 pack is OK to pitch direct into 5 gallons of 1.060. Making a 1L starter with 1 pack will give you 10X the cells, plenty for your brew.
It may be low for Mr. Malty, you may get a slightly slower start (15 vs 12 hours .... example), and you may get slightly more esters because the yeast is a little more stressed (but I bet you would not notice them).
OR pitch both packs direct.