Staples or screws on plywood subfloor? And other questions....

howdihi

We just ripped out our ceramic floor and cement board down to 3/4 tongue an dgroove wood plank. There was shrinkage of this board and not totally firm as lots of springyness. Right now we are putting on 5/8 smooth plywood with the intention of putting cheap vinyl on for a short while and then a glue down cork floor. I have several questions...

1. What size nails, staples, or screws? We put in some screws in the plywood and it was hard to get then a little countersunk. They were either too high or were being countersunk too low. Some of the heads were popping off. We were using 1 5/8 construction screws which i thought was too long and i thought 1 1/4 was too short. I called 2 stores in town and they don't carry 1 1/2 inch screws. Frankly, i was worried that the 1 5/8 might hit my plumbing in the basement. There is A LOT of plumbing in my basement. There has got to be an easier way.

2. What do you use to fill dents and where the plywood meets?

3. How close do you butt the plywood? My local menards said to put them tight together. Though i have heard other advise.

4. Is the plywood sufficient for glue down cork? Or do i need to put a luan down later?

Thanks for all the advise.

howdihi

So i started putting in some screws and about 1 out of 3 were hitting dead space and i had to take them out. This is a pita. This is happening because of the shrinkage of the wood over 60 years i would guess. So, onceagain, does anyone have any advise for me? I put 3 screws into a corner of the plywood and it didn't hit anything. Now, especially, the corners need to be tight. Please help