Fair enough
but I can deal with
some of this right away: the autopilot holds altitude to 10ft, the OAT gauge has been checked with a PT100 (platinum sensor) reference thermometer accurate (and certified to) +/-0.1C but it does display only whole digits so could vary by as much as 1C without it showing, the GPS GS is accurate to better than 1kt, the IAS instrument can be read to about 0.5kt resolution. Heading accuracy is within a few degrees (on autopilot).
I will more tests and report.