Kudos to whomever mentioned Zinsser 1.2.3 spray primer for white tiles

If you wait for a leader you are destined to follow. You don’t need a grand Pooba…you need to try it for yourself and decide. Or be satisfied to follow. Nothing against Norton but his results are his results not yours.
Many of us like myself have been doing this for a while…I know it works better than the Paint Norton uses because I did not wait for someone else to determine that for me. I bought some and tried it myself. I made the decision myself…for me it is better in most applications. Nortons “opinion” may differ…or it may not but it is his opinion. Yours may differ…may not. Only you can decide by testing.
Be the sheep or the shepherd…your choice.