recoil spring rate for slide mounted Ultradot?

I'm going to mount an Ultradot 1" scope on my Les Baer PremierII. This will be a slide mount and I think I'll need to reduce the recoil spring rate to compensate for the extra slide weight. I'll be shooting 200gr LSWC at approx. 720fps. What would you all suggest for a RC spring weight, and should I lower the hammer spring weight as well?

Thanks,
Kim

I suggest you buy a set of springs and test to find which one works best.  Probably be somewhere near 10lbs. 

https://www.ebay.com/itm/1911-complete-recoil-spring-kit-7lb-14lb-government-size-1911-parts-1911/222730622193?epid=1553463575&hash=item33dbc794f1:g:NsgAAOSwa-dWlRBf

As for hammer spring, not sure what comes in a LB, but you may or may not need to lighten it.  Gonna depend on the pistol, load, and trigger weight, etc.  You can finds sets of them on ebay as well.

Thanks Will. I have a low power RC spring assortment coming from Wolf Springs. I'll try the 10lb first.

Kim