I've been pouring over some of the older threads and have learned a great deal about burning my own ROM's. I have an Oric 1 with a single BASIC v1.0 ROM and would like to try out a few of the other ROM's I see floating around, especially the diagnostics ROM and the Atmos 1.1 ROM. I think I found all the information I need but I'm a bit of a hardware noob (I'm a software guy) so wanted to double-check a few things. It will suck to wait a month for everything to arrive from China only to realize I ordered the wrong parts!

First, I'll be getting a MiniPro TL866 off eBay. There are quite a few sellers on eBay and they seem to all come in the same CS an A model (I'll probably just get the CS model).
Next, the chip itself. This is the part I'm still a bit fuzzy on. From what I gathered an EEPROM is better than an EPROM because I don't have to get the UV eraser. As far as EEPROM's go, it sounds like I need to get a "28C" DIP-28 chip, right? I see a few Atmel's that fit that description on eBay but I'm not 100% sure which one will work for sure. Some of the models are AT28C64B-15PU, AT28C64-15PC, AT28C64-15PI, AT28C256-15PU, etc. Which one of those chips will be best use in the Oric 1, or doesn't it really matter?
Thanks!