Dear fellow sexy Ug'ers!

I'm fairly new at amp slaving and have a few concerns with my amp and slaving it to another. I have an '82 JCM 800 and love power amp tone out of it (pre amp is decent as well, but who doesnt love marshall power amp tone). Anyways, I've always loved Metallica's bottom end drive in their amps, but didn't want quite such a "metal" tone. I'm looking somewhere along the lines of hard rock (Aerosmith/Buckcherry,etc) but with a driving bottom end. Anyways, this all leads to my question:

My marshall doesn't have a "line out". Therefore I don't think I can do proper slaving (correct me if i'm wrong, however I think the mesa might have a line out so I can put that before the marshall in the chain). I was thinking about getting a Mesa Mark IV used to get the bottom end, or similar, and use either the power or pre amp, depending on which I like more. And then add the marshall's power amp on top of that.

Will this give me that bottom end but still keep some marshall tonal properties? Or would an a/b/a+b box be a better suggestion to blend these amps together? As well, is slaving damaging to either amps? And is there a certain order these amps need to be in (pre-amp amp before the power-amp amp, etc)?

Any tips or suggestions about my rig from you amazing people would be awesome! Thanks for your time.
dude...slaving means you take the preamp of one amp and cnnect it to the poweramp of another and THAT goes to the speaker...so if you slaved the mesa. you d be taking the slave out or fx loop send jack and connect it to fx loop return on a marshall combo/head.

in general, slaving amp x means that you take the preamp x to the poweramp of another amp.

metallica slaved mesa mark IIc+ combos to marshall heads, so the mesa preamps to the marshall poweramps.
If the FX loop on the Mesa isn't parallel (or the loop can be adjusted between wet and dry), you can take a line from the FX loop send on the Mesa and insert it in the FX loop return on the Marshall. That bypasses the Mesa's power amp, and sends the signal to the Marshall's power amp. Just think of an FX loop as something that seperates the preamp from the power amp; as in, the FX loop is another patch cable in your effects chain.
Only problem however is my marshall is a vintage and doesn't come with a fx loop send or return of any kind. Do I need to get that installed from a technician if thats possible? Would that compromise the tone?

Georgakis187, so if I was to get a Mesa mark (?) for my slaving, would the chain look like this:

Guitar --> Pedals --> Mesa (fx send to marshall) --> Marshall (would need a fx return input?)
--> Attenuator --> Marshall Cab.

Is this correct? I also understand I could place certain pedals between the mesa pre and marshall power amps. But for slaving to work, does one needs an fx send and the other needs an fx return in order to bypass the pre/power amp (depending on which you want to use from each amp)??