D4 and PU, all terms / names for the same product. Moisture curing, expanding ( aka gap filling ) single part glue.
PVA is a totally different thing, and water based.
On bigger floors I use a mosaic trowel ( 3mm notch ) and apply a layer of resin / PVA wood glue onto the floor where the ply is to be overlaid, so you get a near solid bed of glue. Then I screw at at least 100mm centres for a sound nights sleep. The 'normal' wood glues go off slowly, ( unlike the PU's which give you literally minutes ), so with water-based your not counting each second when working. Plus you don't get that god forsaken PU stuff on your hands Also don't forget to liberally glue the abutting joints!
Not many people, especially 'occasional tilers' ( including wa***ers who just own tiling tools ), fully appreciate the importance of this process, and then the customer pays the price down the line when the grout lines start cracking, and then the tiles. Seen it many times, and the aftermath.
Tiles are for life, not just for Xmas