SCv3000 Configuration Issues

Hi All

I know, I know, I should ask my Dell rep for help with this but I have, multiple times, and my Dell rep just isn't listening. While on the phone we worked out a config but given previous mistakes my confidence is low, and now fear I'll end up with a dud. An expensive dud. Looking to community for practical advice. 

From what I've read, the SCv3000 appears to an ideal tool for a 'slim and trim' modernization project. I've done a LiveOptics data grab on my 4 node ESXi cluster and know my 'numbers'. I need a bit under 8TB of usable storage. IOPS peak at 5200 and average (i.e. 95% percent) at a hair under 2000 IOPS. Read write ratio favours write over read most of the day at roughly 70% write / 30% read but in the evening the character changes to 70% read / 30 % write, no doubt a reflection of nightly backup. Daily change is around 500GB but the growth is very low, explaining the low requirement of 8TB.

The initial offer from our rep was 28 x 1.8TB of HDD, which make little sense for an 8TB ask. I'm thinking 7 x 480GB RI SSD for T1, and 10 x 900GB 15k HDD for T2, with the thinking being that if the machine is writing 500GB per day with little change in over all size, the R1 SSD tier would have enough space to soak this up with the lower tier capable of what's not highly active. While MU SSDs would technically be better for writes over RI SSDs, given the low requirement of IOPS, even RI is going have a ton of headroom on the IOPS side.

I got the impression the 8TB requirement was a low ask. I wonder if I can get the performance I need without going overboard on storage size and avoid cramming it full of SSDs and killing the project on price . . .

Any feedback would be great. I imagined the experience with Dell would have been more positive, as it had been in the past, but offering a 48TB when I need 8, I wonder where the disconnect happened.