Changing Fuel Lines w/o the tank
 

I'm bringing my 79 back to life after a peaceful slumber of 20+ years. The fuel lines are brittle and must be changed. So...a few questions for the experts.
1- How do I change out the fuel lines on top of the gas tank without dropping the tank?
2- I saw one posting that said use only OEM fuel lines. Is this really necessary? Can I not just buy several feet of normal fuel line from the parts store and use that to replace the old rubber?
3- Anything special I need to know about checking the cut off valve or other items? You know, those things you never think to ask until it's too late.
Thanks in advance.

there's no other way to access those fuel lines without dropping the tank. and yes u can just buy a length of hose for fuel to replace them with.

Thanks for the response.

I pulled the tank (and received a nice dirt bath) so now I can get to the lines. Unfortunately, when trying to remove a very brittle and stubborn line I broke something but I don't know what it is. I've searched on line and in my manuals but can't find it. It is a small valve body mounted on the floor pan just above the fuel tank. It has one rubber line going in; one port that is capped off; and what looks to be a 10 inch long dump/overflow line that doesn't connect to anything. Know what this is and where I can get a replacement?

Also, the Fuel Vapor Valve on the top of the tank is brittle (chipped part of the flange off removing the line). The rubber gaskets aren't that great either. Should I replace this or maybe just "caulk" around it so there isn't a leak path?

Is there a source of exploded view part diagrams like the old micro phish the dealers used to have? Looks like this is just the first of many little things that I'll be replacing.

I appreciate all the help!

Edit=> I did find parts manuals on Jim Rothe's Mazda RX-7 Page. Very helpful although the graphics are a bit fuzzy so detail is limited.