How easy is it to perform a Stans tubeless conversion without a compressor?

All depends on the tyres and how good you are at pumping 😆

Depends on tyres and rims, I couldn't get mine to work with a pump but co2 cartridges did the job

Using proper UST tyres it's easy with just a floor pump, I've had no probs the few times I've changed from winter to summer tyres and vice-versa.
I've found that if you can get the tyres seated as best as you can without any air in (if that makes sense) the easier it is to pump them up with a floor pump but if you do have a garage close by with a compressor then just use that.

Make sure you pull the tyre bead on each side as close to the side wall of the rim (rather than sat in the middle of the rim section) with a hooked tyre lever and then pump with a track pump. Taking the valve core out helps get air in faster too. Managed racing ralphs, mountain kings, advantages and crossmarks like this without any fuss at all.

I have up till now ran Panaracer Cinders that I've never had any issues with but have noticed that they are not recommended for tubeless conversions.

Can anyone recommend a similar tyre from one of the brands that are recommended for tubeless conversions?