you dont have to flatten floor tiles into the adhesive just a gentle push is all it needs , rapid set adhesive has a natural suction effect anyway. If floor is flat then your tiles will be to
best thing to do is get them tiles up mate, if they r that old you might find that they come up quite easily with hammer and chisel. for a pukka job self level the floor then you have a perfect base for lino
when laying uncalibrated slate i alway remove all tiles from boxes and group together in order of thickness ( time consuming but worth it ) laying the thickest first and gradually working towards the thinner tiles this way your floor will look a lot more even and skirting and kickboards can be...