There are 2 schools of thought when it comes to tape width, you can either go a bit wider than the internal width of your rim so the tape covers the entire width of the rim bed (in your case 29mm rim = approx 32mm tape) or you can go much narrower so the edge of the tape is well away from the tyre bead. Personally I’m in the former camp and have had no problems in years, therefore the kits are no good and you’d have to buy the sealant, tape and valves separately, but I’ve no doubt someone else will come along from the other camp shortly and say buy the narrower kit. Also, it’s worth buying a valve core remover so you can take it out and attach the pump directly to the stem to get maximum airflow to seat the beads.
As for the thorn holes in the tyres, the sealant will soon sort them out. No need to buy new unless they’re badly split.