Yes on the G-26 as a good choice. Electronic ignition will yield easy hand starting and the blessing of not having to fool with a heavy flight box with starter and battery. The only shortcoming of the G-26 is the ignition is power hungry so right out of the box, consider changing to plug-n-play CH ignition rather than investing in high mah ignition battery.

The power difference between the conversion and Zenoah will be dramatic. There are other choices but you implied that you want a rock solid reliable engine and Zenoah is that.