I'm running an 88 FXSTC in QLD and wondered if bolting an oil cooler is a good idea, anyone got any experience?

Wouldnt do it any harm bud.

For a quick check, buy a cheap ($10) digital meat thermometer and measure the oil temp after a hot run.
Any hotter than ~110c and it would be worthwhile .
Evo's usually run decent oil temp's without a cooler.

http://www.ebay.com/itm/OIL-COOLER-ANY-EVO-SHOW-POLISHED-BILLET-SPORTSTERS-ALL-1340-CC-ANY-EVO-NO-TOOLS-/222260544854?hash=item33bfc2c556:g:FI4AAOSwymxVLSKG&vxp=mtr

I've used these on my twincams for years , and have fitted them up to all my riding mate's bikes.

They drop the oil temp 20F , SAME as the factory 2007 and up plumbed in oil cooler system

Best bang for the buck by far these are mate

Oil cooler will help with oil temp control

I found that the cooler collars that retroman recommended aren't bad for the cost v benefit

Oil coolers dont do shit if you aren't moving. Better option are cooling fans, i.e Love Jugs etc etc. A combo of both would be best.

Because these slip on coolers work as a heat sink , they do work even when stopped in traffic. Better than the radiator type systems.

AND they're just as efficient at speed , I've conducted a fairly scientific test/comparison on them in Perth traffic on a hot day a few years back.

There was a thread on this way back then

http://www.hdforums.com.au/Default.aspx?tabid=71&forumid=37&postid=476196&view=topic

^
are these figures, or some that are slightly more 'alarming' ... cause for on concern ?

Yep ....

Uncomfortableness is one thing.

Failure is something completely different.

I can cope with both !

I bought a HD oil filter for my 88,the thermostat cuts in at 185 degree...
It works well

http://www.harley-davidson.com/store/premium-oil-cooler-kit-pa-04-2615707--1