I have the RAM suction mount for my iPad mini and it works very well in both the Cessna and the Bonanza
Cost is not too much different than what you paid for that rig.
RAM Mounts Twist-Lock Composite Suction Cup Base with Ball RAP-B-224-1U with B Size 1" Ball by RAM Mounts Learn more: https://www.amazon.com/dp/B00F54LGJK/ref=cm_sw_em_r_mt_dp_QAM9NJM1317T3P1HXVD8
How did you get the Ram suction cup to screw into the case? (I have a similar problem) Did you start with ball mount suction cup and make a modification? https://www.amazon.com/RAM-MOUNTS-Twist-Suction-Mount/dp/B00F54LGJK/