I was sceptical about ghetto tubeless, but converted when I had an intolerable series of punctures: it's working for me. It must be frustrating if you can't get it to work for you.
Maxxis tyres are generally reckoned to give the best results
Kendas are OK
Panaracers rarely work apparently
You have removed the valve core for initial inflation havn't you? It's impossible with the valve core left in.
Don't put any sealant in until you've managed a full inflation using soap suds - up to 60psi. This step is needed to "seat the bead" into the rim i.e. to shape the tyre to fit the wheel rim. Only when this deflates, do you add sealant. Even if you later "burp" the tyre flat on the trail, it should re-inflate with a mini pump simply because the tyre bead retains it's fit with the rim. [but always carry a spare inner tube just in case it doesn't!]
The trick with the strap around the tyre circumference sound good, though I've not had to resort to that.
This is the hardest bit so keep trying; it's worth it.