Generally speaking, UEFI should not have any problem with a MBR hard disk or SSD, so no changes are needed in there. Divide the storage space as how you see fit. Not having multiple partitions on any size/type of hard disk is a "sign of weakness", as I am a stickler for keeping operating system, programs and data separate. But whatever works for you...well, works for you.
Having said that, please find documentation about your T430 from the Lenovo web site to see if there are notes or specific behavior to be expected when using an SSD. The user's manual usually contains this information. Perhaps there is even a forum where people share experiences with putting an SSD into a Lenovo laptop.
Sorry, lazy Sunday, so I didn't provide links...