If you can see the "Minimum Insertion" marking then you've not got enough seatpost left in the frame to be safe, just go buy a longer seatpost, you can get them in 400mm+ sizes usually (if you need all that seatpost sticking out then either the frame is too small for you or you're some freak of nature
Sooner or later the post will crack, or snap, or both, and it can also break the welds on the seat-tube (happened to me on a low-end steel Raleigh frame).
Having said that, I see no end of people at work riding about on cheap MTB's that must only have a few centimetres of seatpost left in the frame at best, and no one has died (yet).
The OP said he still has more than min. in the frame so should be good.
My advice is to know your frame. Is it a frame that is known for cracking or failure? If it is then there is a reason to be concerned. If not you might be fine. what does the junction look like? I like the old rockies where the seat stay come in above the top tube and the slot it on the front. This gives the post and junction more support where it is needed, at the back near the seat collar, it's a great design. As long as you post is extending down below the bottom of the top tube by say, an inch, you should have plenty in the frame and you should not have an issue damaging the frame though you could always bend or crack the post is if is a lightweight because there is a lot of leverage on there.
Black Syncros handlebars with shim
Rocky Mountain shoulder holder or similar era saddle
Flight Titanium red logo saddle in very good condition