Yes for one more slot this would be 0x150 (138h+18h).
+138h = pointer to start of 50 byte ingame save description strings (12*50 bytes)
32h 50 dec is size ingame save description strings (ignore this)
many 120h are (0xC * 0x18) -> i.e. hidden cmp 0xC checks for slot loops
So 120h and 138h -> each +0x18(24dec) per new save slot
And I agree with thunderchero, we need a project patch with all code values labeled with asm locations to help (cf. my newer patches).
Good news is sub_4F0250 loadsave_ESP doesn't seem to need esp adjustments (only 4F02A1/120h 4F0375/138h) and there is no MP issue.
So I guess about 70 values: one 0xC, many (0x120, 0x138, 0x390 and 0x394) one size 0x3C8
As told -> 0x120/0x138 each +0x18 per new slot -> 0x390/0x394 and 0x3C8 each +0x4A per new slot
Plus all the widget/wdf stuff (e.g. four for total number of widgets cf. xrefs to wdf widget IDs).