I think its pretty normal in any sport, I know for basketball i would practise moves for hours. But come game time i would stick to a couple of moves, you have to make a conscious effort to actually do them for them to come natural. There is no strict time frame, just seeing openings and filling them. Plus since those are mainly close in punches it does take some learning to do them in the ring. I know i hardly ever throw uppercuts, but thats because I try not to stay close to sparring partners for very long at all. I guess you need to set out in a sparring session to actually try and do these punches, and aim to creat openings for uppercuts and hooks instead of straights.