R730 Memory Upgrade and Configuration

Hello,

I have a R730 with 2x E5 2670 v3 and 2x 16 GB - 2RX4  RDIMM  2133 MHz. I am thinking to upgrade the memory with 2x 32GB - 2Rx4 RDIMM 2666MHz. In R730 owner's manual, it is said that frequency can be 1866, 2133 or 2400. So can this 2666MHz memory module work at 2133MHz with 16Gb-2133 MHz memory modules without any problem? For the populations of the module, I think It should be 32GB to A1-B1 and 16Gb to A2-B2 slots, If it is wrong please correct me. I am adding the memory modules link below. Thanks for your help.

https://www.dell.com/en-us/work/shop/dell-16gb-certified-memory-module-2rx4-ddr4-rdimm-2133mhz/apd/a7910488/memory

https://www.dell.com/en-us/work/shop/dell-memory-upgrade-32gb-2rx4-ddr4-rdimm-2666mhz/apd/a9781929/memory