Bill, The active PH's that aren't outfitters are getting busy right now with hunts so you may be stuck with us retired PH's and outfitters that have the time to get on the net more often!
You're 100% right to ask ALL the questions before you get mired in something not well thought through!
Hunting in Zimbabwe, NO ONE can tell you he'll guarantee a Kudu of X inches...the properties are unfenced (except for a handfull left now) and the populations are migratory to a large degree....or have a large Home range to be more accurate. Other forces such as poaching in general and with dogs also put a spanner in the works. So in Zim, you'd take your chances but no one charges by the inch. However, the PH could pretty much call the Kudu within an inch or two.
Jaco could well correct me here, but in SA, a lot of properties are very small and the outfitters buy their game in for the season from the auctions. Thus they know what they've bought and can charge per inch. Those more fortunate with larger properties ( like Jaco) have their own home grown sustainable population and have historical average length records. He'll also know that there are bigger ones around on the property. Elsewhere in these threads is a gent offering hunts in the eastern cape stating that he has over 100 000 hectares of area. What he doesn't tell you is that they are most likely 3000 acre at the most each and they're spread through out the whole eastern cape and should you hunt with him, you spend a lot of time in transit moving from one hunting property to another across the province. So the hunt is not exactly relaxing in one camp as much as getting to see a whole lot of highways and small fenced properties.
At the end of the day, your research needs to center on exactly where you'll hunt, the size of that property, speak to clients that have hunted Kudu there,
if you are expected to pay by the inch, then the onus is on the PH to call it exactly. His 'under call' mistake should be to your benefit and not charged for. If he's 'ify' about a borderline call decide for yourself decide for yourself whether the animal is a wall hanger (and you can afford it) in YOUR trophy room and whether the story of that hunt will last in your memory when you gaze at your trophy. As a PH, I found that that huge trophy that just happened to be standing on the side of the road and got shot from the truck door amid the dust was an emotional disappointment versus that 'lesser' trophy that gave us a run around for hours ( that has a real story to the hunt!).
That 'broomed off' wily old Kudu bull will be the challenge rather than the young inexperienced sharp pointed one! That is why, in my humble opinion, SCI scoring doesn't benefit the populations of African animals as it favours the longer horned younger 'prime breeding' aged animals over the old bulls which is exactly opposite to the antlered animals in the US.
As an aside, I often wonder what people have to say to their friends when they have shot a caged Lion and had it mounted in their trophy rooms...my skin crawls at the thought of lying to my friends to justify what I've done!