I am currently running a 9-region sim (Diva installation, i.e., standalone HG with MySQL, but I removed the default megaregion configuration) on an i7 920 processor, 8 GB RAM (could add more RAM, but haven't had a need yet), GeForce GTX 560Ti graphics card, over cable modem and a router (up to 4 PCs connected on home network, but usually only 2 operating).
I'm still working on terraforming the 9-region sim, and once that's complete, I plan to copy over the OARs to OSGrid. I expect very little traffic. Generally just me and occasionally two others. The problem is that the edges of the sim are ugly (tall mountains). Although I do plan to locate my sim far away from anyone else, I would find it offensive, so I just won't do it like that.
First question (which begs other questions): Should I be able to surround the 9-region sim with very low prim regions (mostly low prim count landscaping) for a total of 25 regions? If not, if PC capacity is the issue, I could probably talk my husband into hosting some of the regions. If BW is the issue, then maybe I should keep it standalone? Should I use megaregions? And even if I could manage it (in all senses of the word - I suspect region management will be the biggest hassle), should I even try to port this over to OSGrid? Is 25 regions a bit over the top for 1 or 2 users on OSGrid?
Second question: Is there a reason I should use HG on OSGrid? I don't plan to grid hop, and the only time I've used the HG capability I have now is to go to OSGrid. I plan to keep the Diva installation and just start from scratch on the OS Grid installation, so I'll still be able to grid hop if desired.
Thanks in advance for your suggestions. I'm still in the planning stages, so it's not too late to talk some sense into me.

Edited note: forgot to ask - if we do run this from two machines, what is the best way to split it up? Such as one machine handling regions, one handling database, etc.