If I was you I would take the die with stuck brass to a gunsmith. Most gunsmiths have had dozens come in and he more than likely will have a puller. In my opinion the 10 bucks or so spent will be worth the frustration and if your smith is any kind of guy he will walk you through the do's and don't's. Being in the frustrated mode makes it difficult to see the light at the end of the tunnel.
As far as using spray lube - I too have used it for 15 or so years with no problems.
I roll out enough paper towel on floor or cookie sheet, stand brass upright, spray all four sides at a 45 degree downward angle and then go over the top to spray down into the necks. I let lube dry on brass for 10-15 min before I touch brass. With that said I have a can of imperial die wax and as I am resizing, if one seems to have a little resistance - and it is always on the upstroke - I will take the next piece of brass and put just a small amount of Imperial on the inside of the neck and things seems to have no more resistance for quite a while. If I get to the point where it seems it needs it again I repeat appl. with Imperial. So I guess I use both spray and Imperial but I will say I haven't used enough Imperial out of one little tin in 15 years that you'd even notice it.
I tumble my brass before resizing, wipe off as much lube with paper towels after resizing, then I will re-tumble again for a short time to remove any wax that I missed.
As far as cleaning your die. After EVERY reloading session I take my die apart, spray inside and all parts with "Mercury" cleaner and let them set on a paper towel on my reloading bench until I return - may be as long as a couple days sometimes. The mercury cleaner I use I got from a boat mechanic and I believe it is called "mercury power tune engine cleaner". *( Best dang cleaner for pistol I have ever tried and it flat gets the powder residue etc.). Wipe your die down/out with cleaning patches and put away until the next time. Do you need to clean a die every time - No probably not - but my memory is as long as some other parts I own and I found if I do it every time I know it's clean when I go to use it again. I have some dies I may use only once every 2 years. This works for me - if I stay with what I know works I seem to have better luck.
I am not familiar with Forrester dies but there should be a vent hole and that can not have any restriction from old lube etc. or are going to continue to have problems.
Went through the same same frustration you are going through some 40 years ago but if you clean your dies - use adequate lube - things will go well.
Oh yea - about the time you figure you know everything in this game - Murphy shows up every once in awhile. Great hobby isn't it.
Good luck - sorry to be so long winded.