Anyone know how this angular torque gauge works

[apple snails]

I'm looking to buy a angular gauge for when I do my head gasket but I don't know which one out of the two will be the best to buy. The first one has a stop but I'm not to sure where I would place the stop on the engine. So if I bought the second angular gauge would anyone know how to use it as it doesn't have a stop but has a flexi arm.

 

[MoreWellie]

I have the first one. All the stop has to do is prevent the inner dial from turning which takes minimal effort. The stop swivels and can be refitted both ways round and has been easy to get somewhere against a flange on the cylinder heads we have used it on

 

[apple snails]

I have the first one. All the stop has to do is prevent the inner dial from turning which takes minimal effort. The stop swivels and can be refitted both ways round and has been easy to get somewhere against a flange on the cylinder heads we have used it on

I did buy one like in the first picture but never used it but now I need it's gone missing

 

[MoreWellie]

somewhere there is a massive pile of "lost" tools, I recently lost not one but two set squares in the same week.

Just in case you are wondering, I can probably find the receipt where I purchased my dial gauge