If you want to keep things simple, and keep costs down, get a tonearm with the same pivot-to-spindle distance as the original arm. Otherwise, you'll have to drill a new hole and deal with mounting it correctly. I don't know what tonearm came with the DD-24, but it probably has a mounting distance of 222 mm. Most (all?) Micro Seiki arms have an effective length of 237 mm and an overhang of 15 mm (237-15=222).
Any Rega arm should work well with this table. RB-250, 251, 300, 301 often come up used for $200-300.
