Hi,
Running my CX wheels tubeless this year doing this.
Mavic 719 rims with Schwalbe CX Pro tyres.
Used insulating tape to build up the rim well. You need to get it so that the bead is tight on the rim seat. You also need to make sure that you build up the centre well enough that the tyre bead is air tight as this make inflating the tyre easier.
Puncture a hole in the tape for your valve (one cut out of an old tube is fine). Once you have the valve in it is a good idea to put more tape over it to help with sealing (remember to put a hole in the tape for the air).
Fit the tyre to check that it is tight enough. You can sometimes actually get it to start to inflate with a track pump without sealant if you get the rim taping just right.
Unhook a section of the bead and pour in your sealant. Refit the tyre and then spin the wheel, rocking it from side to side to get the sealant around the tyre.
Pump it up to about 40 psi using the track pump (if it won’t inflate you need a better seal, add more tape). Once it has been inflated you should see sealant sealing the bead and any holes in the tyre casing.
Do a short ride up and down the street to help get the sealant into all the nooks. Leave it overnight and hopefully it will be sealed.
With my CX tyres the front sealed first time, the rear leaked about 20psi on the first few rides. It sealed after that, sometimes it does take the extra rides for them to fully bed in.
Cost
No tubes sealant £15
Insulating tape £2
Valves free
Regards