Have just edited my posts...I have a CT20b rev 3 Turbo not a 26...my bad.
Hope the advice is consistant with that alteration?

Hi Guys, I'm back on the turbo horse!  As per various suggestions I've had compression checked and pretty uniform and around 170psi.  Plugs were grey, dry, not oiled.   I've fitted a catch can as suggested earlier.  Still smoking so I'm back to turbo and bought a $1200 Mamba turbo rather than mess around with rebuild.  Came with a nice set of hoses.   Which leads to my question.  The wastegate actuator on my original CT26 has a pipe nipple on it which has a hose to a nipple early in the compressor snail path.   The Mamba turbo has this point blanked off and a nipple way at the end of the compressor snail, just between the "CT26" label and the outlet.  My Toyota CT26 didn't have any way to connect at this point but I noticed it seemed that the casting was thicker there, as if Toyota had allowed for this?   Should I run the actuator hose to the point that Mamba seem to intend or switch back to the Toyota pressure point earlier in the snail.  The forum doesn't easily allow me to add a pic, I don't know how to do this easily via URL, sorry.  I've tried to get Mamba to reply but no luck.
 

Run it where mamba has it.

Monitor your boost pressure gauge vs actuator movement.

For the love of your mr2. Please regularly get your injectors out and ultrasonic cleaned and flow tested. Please invest in a wideband for air fuel rations especially if dialing up boost (just race parts - cheap for quality).

Thanks Tony.  And for the other suggestions.  I need to sort out the oil in exhaust before going to wideband sensor, my exhaust seemed to foul the last w/b sensor that I had fitted so I went back to std one.  I'm not even sure if it is working:-(

I don't know what it's like if your intercooler has collected a heap of oil from a bad turbo, but most of the smoke symptoms you described sound like engine problems to me. Especially things like after the engine sits for a while, then on startup gives a puff of blue, sounds like valve seals. Another symptom of valve seals is after engine braking for a corner as you drive out of the corner another puff of smoke, then nothing. Rings is under power up a hill, smoke more continuously. Head gasket...blue smoke is more like valve seals in that oil needs to be sucked in, ie throttle shut.