Joe,

A 17 Lbf turbine will happily fly the Reaper around without any problems.

Almost all the engines in the market today offer Electric start, so no problems here either.

As for fuel efficiency, all the engines consume the same amount of fuel more or less. It's in your hands to increase or decrease the fuel consumption. The Reaper will be very happy flying at 1/4 throttle all round. You can get ten minute flights easily with that. It won't go much faster if you fly full throttle.

As for 12 lbf turbines (smaller in size and lighter in weight), there are three in the market today and a fourth one coming soon, as I understand. The ones available are: Simjet 1200, RAM 500 and the kit-built MW54. The Artes/TJT Bee 50 is on its way. You can buy a KJ66 type engine and de-tune it to lower the maximum thrust , but I do no recommend it, as you'll need all the power you can get on take-off.

Best regards,

Chris