Can someone with a small frame JP take a measurement for me?

[Mnash]

I'm looking to see if i can run my ZCO 527 / spuhr 6001 setup I currently have on a JP CTI-23 Upper. As is sits the scope bell is 1.5mm below flush if there was a monolithic pic rail. I know the JP handguard sits lower than the upper receiver pic rail. Does anyone know, or can anyone who has one measure for me, to see what that gap is? Alternatively if you have the top rail section for the handguard you can just gauge that and it'll tell me. I know I should just run a 1.5" mount, but I dont want to lol.