First, let me appologize for the long post:

We recently purchased a home built in 1870 with a two pipe steam radiator system, including all of the original radiators. We are finding that the downstairs is significantly cooler than the upstairs (more than just the typical "heat-rises" factor) and one bedroom upstairs is so hot that it is nearly impossible to be in it for more than a few minutes, even with the window open and temps here have been in the low teens!

It may be worth noting that the downstairs had an addition made to it sometime during the 70's and has hot water baseboards--this room actually tends to be almost too cold. We have also noted that upstairs radiators feed first from the boiler. Amazingly, the house had insulation added to it (we are guessing around the 70's as well).

Any ideas on what we can do to "cut the heat" upstairs to a more comfortable temp? Is simply closing the water valve down a bit to reduce water flow effective--or is it detrimental to the system?

I have seen a lot on here about the thermostatic radiator valve controls, including the video, for one-pipe systems. Are these available for two-pipe systems?

Thank you in advance for any advice/solutions!!