I agree with that article to a large extent. I do agree that the best way to learn DE shaving is to junk those aerosol cans, & start using a soap/cream, a brush & the user's old cartridge razor.
I also agree with the idea of using a DE & a cart for the second step. Where I disagree is the order of usage. A DE razor has the ability to cut down longer hair better than a cartridge razor, so the DE should be the first razor used, & the second pass should be with the cartridge. Cartridge razors do have some advantages over DE's - among these are pivoting heads, greater blade rigidity than any DE razor, skin stretching fins before the blade, & skin smoothing/friction reduction gel strips after the blade. Their disadvantages are too many blades & the lack of ability to mow down longer stubble. For these reasons, the cartridge razor should come after the DE.
And, I have tried out this combination. As earlier mentioned, I sometimes do a single WTG pass with my DE followed with a cartridge for an XTG on the days that I don't quite feel up to a full three pass shave. I get equally good results, & no skin irritation. (I'm prone to PFB.)
It's quite possible that the skin stretching of your WS Protector cart & the gel strip is what makes your skin not flare up.