I like your idea of the solid bung stopper to pick it up but, for ease I promise a 6 gallon better bottle fits great in a milk crate and serves the same purpose of preventing suck back...... there should be a poll how many better bottle user use the milk crate method I bet the percentage would be pretty high.Hmm they dont mention if the Spiedels are made out of PET plastic. Thats a concern
They are made out of HDPE. Don't ask me what that means though.
It means that it'll let gas through. If you need a good degree of gas/oxygen impermeability then PET is the way to go.
As far as the airlock sucking when you lift a plastic carboy, I deal with that by just replacing the drilled stopper with a solid one before picking it up.