The training problem is mainly associated with the newly completed aircraft. Your Airworthiness Certificate, allowing Phase I flight testing, precludes carrying passengers during Phase I. Most insurance, precludes using your aircraft for training, other then for your own recurrency training in your aircraft. The cost to obtain a "Training" insurance policy, to provide third party training for our aircraft types, if obtainable, is excessive or outlandish. This leaves the builder with the Catch 22 problem of getting prior familiarization training before Phase I. As Jeff has pointed out many times, the highest risk is in the 1st 100 hours., either the builder or new to type owner.
Giff Marr