I like it, but much prefer
Octavian. I don't think either of them's too much - long and honourable history, and they can always go for Tay or Tavi (or Tavian if applicable) if they decide that the full four syllables are too much.
Just working from your profile list, wdyt of:
Andrew OctaviusCorin OctaviusMatthew OctaviusOctavius PeterOctavius Conrad