@Ulrich_Baer , thank you for sharing so much info. I’ll try calibrating my layer height as suggested.
@Panayiotis_Savva you’re welcome, btw pva is the main ingredient in gluesticks or paper glue. From what @ekaggrat_singh_kalsi suggested I am using an Ipad 12.9" display protection (the only apple product i am finally using) - that is a 0.26mm hardened glas (very even but still a little flexible) with a silicon film beneath (works as compensation for equalisation and add a little safty buffer zone). Ontop I add Kapton, below the glas is the heated Aluminium. (only a machined alu block could be even leveled flat - the sheets/tiles are not) … keep in mind to calibrate the hotbed when it is hot.
I generally use wood glue applied with a credit card.
if the above image is of the print model it looks like it will have a lot of internal tension witha high warping rate and relatively low surface area to bed contact.add in the no heated bed and it’ss be tricky to do. I’s try printing on a raft (should give more surface adhesion) and make sure your printer isn’t anywhere drafty 
tldr; the whole thread, but I use purple (not white, purple important) glue stick directly on glass, heated to 60 deg. Once I switched to that, I can’t remember the last time I had a liftoff.
This is how I work with an unheated aluminum bed.
First, with no tape, get some 91% isopropyl alcohol, and a small piece of paper towel, rub down the bed, if you see dirt or grease on the paper towel, go back again with a fresh one. Wait for that to dry and apply blue tape. I use the 3m stuff but I have heard good things about duck brand blue painter’s tape. Then clean the tape the same way, and take an Elmer’s stick and completely cover the bed with a thin layer. If you have too much, wipe some off with iso alcohol again. Then wait a few minutes and print. The glue lasts a few prints, but clean with iso alcohol before every print.
@Alexander_Pritchard I’ll give it a try now