Mate, it's entirely up to you but the 'norm' (if there such a thing) really all depends on what country, area, company and type of hunt.

As an example, you can spend something like (excluding trophy fees) US$45K on a 21 day full bag safari with an average company or you can go right upmarket and spend US$100K+.

'Average' tip (just for the PH) on the former might be between US$500-1500 whilst the latter could be several times that...... very occasionally on an ultra luxury hunt it can be several tens of thousands....... but that's nowhere near normal by any means!!!

At the other end of the scale a plains game hunt in somewhere like SA might be a couple of hundred dollars in total.

Other factors might be things like your own feelings, culture and even income/affluence.

Personally, I don't even think about how much a tip will be and in some ways, esp from old hunting buddies, I'd prefer something like a book rather than cash........ Had a regular hunting buddy this year who gave me a 1923 copy of the RW handbook and was/am pleased as punch with it. (I am a serious book collector though)

I understand you problem and probably the best thing you can do is ask the outfitter (NOT the agent) when you're doing your research/