Now that's a poser.

Those numbers are "quality," not signal level, so it is just plain hard to tell.

If the signals are screaming hot wonderful, but have some multipath therefore making them less than, say, 95, amplifying those could introduce distortion and make them worse.

If they are not great because of signal level, amplifying them could make them better or leave them as they are while improving the other one.

Or the other one could be adequate in signal level but have loads of multipath, so re-aiming would be a thing to try first.

I would take advantage of someone's liberal return policy (Radio Shack?) and get a 10 dB UHF antenna, after checking at www.antennaweb.org to be sure the signals I want are all UHFers. And if not, then get an appropriate amp. 10 dB of signal increase should definitely fix or mess up what you have, and there is always that return policy.