looking to buy and restore a tough ol cruiser, looking for opinions of models in xt - xy range and hints/tips on what to look out for in purchase. any help greatly appreciated, plan is to convert to 250 xflow heart but is just a basic plan at this stage. thanking in advance, me.

The hardest part will be finding a nice straight one. XR, T, W or Y is up to you. XR and T will probably be cheaper to buy, but harder to get parts for. But resale on a XW or Y will be higher. I'd go for an XY Fairmont personally, and not just coz I own one!!
All the cars in this group will have rust, after all they are 38 - 35 years old.
Check these areas:
Front subframe, below radiator
Sill panels, inner and outer
Bottom corners of rear window - check from inside boot too
Boot rubber channels
Roof gutter seams
Bottom of front guards
Lower corners of door skins
Inner door frames along bottom edge

My car has been in the panel shop for last 6 months fixing rust and getting it straight, and it looked pretty good before I stripped it!!

Who cares? XR, XT, XW, XY all look great!
Like Smally said, check the body for rust! Also look at the litle things like chrome fittings, grile, lights, dashpad and the like, such things can be expensive and sometimes hard to replace.

Id go a XY GTHO Phase III

Yes, parts can be expensive. I bought a complete XY for $300 just because the grille was good!

watch out for the vinyl roof fairmonts, might look good but also good at creating rust.

check out this site

http://www.perfordmag.com/

and check out the how to section