I've done a little research and found a few possible answers in the achieves but would like to get some more specific answers about importing an experimental homebuilt glider.I'm interested in importing a Schreder HP-18 that was built in 1978 and has over 2,300 hours on the airframe. Unfortunately the third owner has no build logs, plans, pictures and only very generic maintenance records which consist mainly of yearly Canadian "conditional inspection" forms with little detail about what maintenance was actually performed. There are a few one line entries in the airframe journey logbook but other than that no maintenance records. I have inspected the glider and it is in pretty good shape so it has obviously been cared for even though there are no records to prove it per say.The problem I face in trying to import this glider as an experimental amature built is how will I be able to prove that it is in fact amature built with no professional commercial help ie 51%+ owner built. With no build logs or records of any kind will I be able to use the Canadian Airworthiness certificate as evidence that it was indeed homebuilt? The records show the original owners/builders as the manufacturers and HP-18 as the type. As an alternative to importing it as amature built I assume I could import it as experimental racing/exhibition although doing so would bring operating radius limitations as well as yearly program letters with schedules and the associated hassles. I would rather certify it as amature built if at all possible.Any help would be greatly appreciated.Greg