The mistake most people do is to connect the throttle and boost lever. This was only introduced for ease of use during combat at high altitude. Normally you should never do that.
And you should never advance the boost beyond the throttle.
My advise for people with 2 axis available is to bind throttle and boost, not the prop in this bird.
Then climb is easy:
1. From the ground upwards, the boost stays off, only fly with throttle.
2. at about 5-7k feet, your MP will drop below what you want, and you introduce boost.
3. Continue giving more boost as MP drops while climbing. At this point the boost lever is your throttle!
4. Somewhere around 30k feet (can't remember the number) you cannot boost more, or you will overspeed the turbo (light comes on) Now start gradually reducing boost, just enough to keep the light off.
I was able to reach about 40k feet quite easily doing that. At that point i could not introduce more power. I am sure more will be available with WI, but thats not for cruising anyways.
Hope that helps. :)