That method is good... but first try putting a protecting layer on: take that scotch electrician's tape and wrap once where you started at the bottom, then reverse the tape so the sticky side is out, and apply all the way up to the connector like you showed. Then do the application of the stretchy sealant and final electricians tape like you did over that base layer.... If you ever have to remove the water proof application, one careful slice and it all comes off easily and leaves the coax as clean as the day you put in all on, with no sticky residue or anything at all. Thanks for that vid!
I've been hearing that feedback that doing the reverse really helps with removal. I've had to remove the 'Coax Seal' brand and that is a real nightmare. It's incredibly gooe'y. Certainly going to use the method you described on my next antenna that goes up next Spring. Thanks for the tip!