A less desirable vintage will never be worth more than the more desirable, simple and clear. Any attempt to make it so will be negated by loss of originality. So, stay true to your chosen path and spend as little as possible on this restoration. Whenever possible, try to bridge the gap between little money and good results by applying more elbow grease. Just make sure you have fun in the process.
But if you really feel the urge to spend major $ and do it right, punt this one and start with another from the 72-73 range.
Finally, there are far worse things than being upside down on a vintage Porsche. Don't let that possibility take away from the fun.
PS,
And as far as a current value for a 69T, words can't even describe how subjective that would be. But if you subscribe to what I said above, who cares?