Well the flying weight is 24oz. but that is assuming you are using a .049 and fuel. You are not going to find anything in a battery and motor that will weigh that little. So guestimate a 30oz plane. This being a sailplane you really don't need that much thrust so go for around 50W/lb gives you 125watts. Any ol brushless setup will get you there. Here is the cheapest option I know of.
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