How not to bleed the clutch

[GS535i]

After a couple of days on jack stands doing preventative issues while waiting on a set of tires, I bled the brakes and clutch - using a home brewed pressure bleeder ( small precision regulator & gauge connected to a reservoir cap with a swiveling legrange fitting - connected to an air supply).
Jumped in today for a test spin - and the clutch snapped hard to the floor .... During a perfect bleed, I had stupidly & and inadvertently filled both master and slave with air.
I had assumed that the master cylinder fill line came off the bottom of the reservoir - where any sane person would have anticipated it: BMW placed the fill point ~ 2cm from the top. The result is that with a reservoir ~80% full, one blows pure air into this elevated take off!!
Please be advised to avoid my error - when bleeding the clutch, keep the reservoir absolutely full: doing this, the air was quickly displaced.
Am I the first to pull this dumb stunt - or amongst the first to confess?

[gale]

I did mine with a homemade weed sprayer contraption pumped up to 5 psi, with the slave cyl. removed and raised up thru the hood as far as it would go to make the vent valve a high point. I strapped the plunger rod in place with a metal band to keep it from hyper-extending, and could keep an eye on the reservoir level at the same time. As a sanity check, I bled a few more cc's out of it after installing the slave cyl. & it worked great the 1st time. I put a hose clamp on the ends of the hose from the reservoir to the master cyl just in case they wanted to pop off under pressure. It would have gotten ugly if I let the fluid level get too low since I hooked the clutch supply line to one of the spare nipples on the brake reservoir & skipped mounting a separate clutch reservoir.