Yes, in my opinion, it would be fine to use. You won't hurt anything if that's your concern. I used my 7336 for over a year with a 5" counterweight and 6" BP and larger pads. Once I got my 6" weight it simply reduced the vibrations a bit at speeds 5-6 but didn't change the results I was getting.
If you think about it, a 5" weight is trying to "throw" a 6" BP and 6.5" or 7" pad = more weight and diameter. It can't keep up and is trying to work too hard so you feel the difference.
6" counterweights are available from many online suppliers and it would probably be a good idea to get one if you're ordering supplies epsecially if you use your PC for long periods of time. It will improve the comfort level for you.