As mentioned above, shrimp can be very sensitive to CO2 in addition to the swings it will cause. If you absolutely want to try it out, lower your CO2 injection to like 1 bubble every 3-5 seconds and gradually raise it over the next month or two.
Generally speaking, shrimp are not super compatible with high-tech or community tanks (depending on the inhabitants), so I wouldn't really expect them to breed and you might just see slow "unexplained" die-offs over the next couple weeks/months.
Your winter gH might be high enough to cause molting issues as well.
I currently have 3-4 amano shrimp. They have been living in the tank for 4 months together with tetras, guppies, Siamese AE, pleco. They seem okay as I see them freely swim about going from one plant to another. They used to be very shy, but about a month ago they started mingling with the community.
Currently I am dosing 38 ppm of CO2 which lowers the pH to 6.8. But as you said 38 ppm may be a little too much for the shrimp I am going to get this Saturday. So I am planning to lower the CO2 to around 15 ppm which will raise my pH to around 7-7.1.
And instead of turning CO2 off at night, I will keep it running to maintain constant pH levels. I don't think 15 ppm of CO2 will be too much for the new shrimp. Every week, I will lower .1 pH until it reaches around 35 ppm for CO2.
In the summer months, I have seen my amano shrimp molt. But ever since winter hit, I haven't seen a single molt. I did not know high GH causes molting issues. I will probably need to use RO water as a supplement to lower my GH.
My high tech tank saw the most prolific breeding in any tank I've ever had.
Yeah, I have heard and seen high tech tanks with 40 ppm of CO2 have very nice thriving and breeding shrimp colony as well. When I saw that, I wanted to add some shrimp to my tank.
My guppies have character, but I see that shrimp have some funny personalities as well.