I told you on Facebook that one inspectors interpretation is one inspectors interpretation. Then FSDOs vary from other FSDOs.
No matter which way you go, suction cup or something better, prove it. Prove it to yourself, prove it to an ASI conducting a ramp inspection, prove it to anyone that asks.
If it isn't in writing, it didn't happen. Even if it is in writing doesn't make it right. Don't bet your certificates, especially something trivial and stupid on what someone else said or what you assumed.