200 volts is the rated voltage of equipment intended to be used with a 208V supply. I have a couple of Rockwell machines with 200V 3Ø motors dating back to the early 1970's, both the shaper & 7" grinder were former school machines & they both run off a 240V 1Ø supply with VFD's.
The CH panel was the highest quality load center available at the time Eaton cheapened them since then but they are still a desirable panel & has a copper bus unlike SQ D Homeline.
I lived with a 10 gallon electric water heater many decades ago learned to shower quickly with a low flow shower head would have been better but was not a option, a 10 gallon WH on a timer would work well.
There are some who say DP stands for "Don't Purchase", that DP contactor is not a listed product so it is unwise to use it for anything other than replacement on listed equipment.
The Little Kickers have gotten rather expensive over the years, paid $189* for my 1/2",& $10 for a 3/4" at a yard sale that a electrical contractor was having up in Paradise, CA before the Camp Fire.
*See that they are over $300 now. (n)