Fitting a pre-owned wood block floor

[Rimrogs]

I've obtained a used woodblock floor which I'd like to lay in my screeded hall floor. The blocks are t&g and I still have to scrape the old adhesive off (not bitumen).
As the original block floor had been sanded (poss several times), the blocks are different thicknesses above the tongue and I'm puzzled as to how I can lay the floor level....or is this project just impossible?
Any ideas?
Also, any tips for removing the old adhesive...I'm resigned to a paint scraper & elbow grease at the moment?

 

[big-all]

blimey possibly a nighmare

removing adhesive !!!!! dont know depends on type but if it wont come off with a good scraper or sharp chisel you in for several hours of hard labour
the only choice you have with regards to the different thicknesses is to lock and lay them together and when the adhesive is dry sand