hi i have one as well (a GSP one)
flys good.....has a few issue`s....
the covering is not great..(cheap ARF so i cant really complain)
wheels work well. but will be worn out in no time.(especially rear)
wheel pants are sort of cheezy(easy to get hammered/garfed)
and getting wings off and on..takes some practice.....(the springs)
fuel tank should of been mounted closer to CG( i put in front for now like directions stated)

and your right. the instructions are..."vague" to say the least

you can balance it at 125mm.... from the leading edge where it tells you... will work fine... did for me

today i busted landing gear ( i am a dork sometimes) had a problem hearing my engine because of a ultimate bipe in the air and was going to slow...i fixed fuse... need new gear.. looks burly.. but i don't think its as strong as it looks..

mine is no power demon.. but is fun to fly
nice inverted.. nice knife edge..(does not want to roll out)
predictable..
canopy is tough.... i liked it.used canopy glue and a few screws... worked and looked awsome

working through small hole in bottom is strange.. i wished top came of like most