Hey, I'd think the deep part may be in the wrong place for clearance, I seem to remember someone on here doing it and cracking the sump on the diff. Still I'm going off my rb25 motor swap but I think it will be similar for you. My motor was from an r33 and the sump would have hit the diff etc so I just used the rd28 sump, bolts straight up and clears everything. Swapped the oil pickup and you also have to move the dipstick, there are two spots it can go in in the rb block, just have to use a punch to knock the dipstick tube up and out (from the bottom of the motor with the sump off) and knock out a brass plug that fills the other hole (same side further back) and swap them around. Make sure you get your head around the dipstick length, tube length and final oil level with whatever combination you end up using. If the rd28 sump doesn't fit your rb30 block for some reason (think it should) easiest would be to look for a sump from an rb30 patrol. And use a good liquid sealant designed for the job, they don't have a gasket.
Cheers, so you basically swapped the brass plug hole to where the dipstick was and put the dipstick where the brass plug is, and used the same ones????? if i used the sump and swithced the dipstick around.... i shouldnt have to keep an eye on the oil level once i filled it should i, being it would hold the same amount as the RD28 engine anyway????