Silver-Cased Pretty Little Watch Unknown Maker

[PWFDmedic]

Greetings everyone.  I picked up this off an international auction, shipped from England.  The case is 0.935 silver, which I thought was a promising sign of possible quality and/or value.

I'm still very much learning how to do all this.  I discovered both friction-fit jewels that are broken, and a broken mainspring.  I focused on other, simpler watches for the past year, and am now getting back into this one.  I finally bought a jeweling tool, which is the skill that was holding me back on this watch.  Now I'm ready to take care of the jewels, but as for the mainspring, I don't know what to order since I don't know the maker.

The mainspring is 1.65mm tall, 45 cm in length, and I have identified how each end should be, but the thing I am most unsure of is the strength of spring I should order.

In the absence of any other information, I was thinking simply ordering something "middle of the road" would be my best option.

But the people in this forum have been amazing in identifying another watch I had earlier, so I thought I might try again:

Attached are the photos I have of this watch.  The Depose' RV engraving is present, but no other hallmarks or other trademarks are present on the base plate or movement that I can see other than the case.

Any ideas of: (1) what the maker might be, and (2) the strength of mainspring I might need to order?

Edited September 15, 2023 by PWFDmedic

[RichardHarris123]

Measure the thickness of the mainspring, that's the strength. 

[PWFDmedic]

My goodness it's that simple?  Thanks so much!

[RichardHarris123]

You're welcome.  What sort of end is it? 

[PWFDmedic]

The hole end is the "H" type on the Cas Ker web page, and the other end is the regular Swiss tongue end.