I have done a fair amount of experimenting with stuff in the center between speakers. With dynamic speakers (as opposed to ribbon), you do not want a stack of stuff… it screws up the imaging. I had to locate my equipment off to the side… that and the addition of a thick wool wall hanging (see photos under my UserID)… made a huge performance difference. The soundstage now goes deep into the wall.
Also, you do not want to put long interconnect between the TT and Phonostage. Typically, as mentioned above you break between the preamp and amp. So with no choice… you’ll have to go with long speaker cables. This is hard because: 1) quality matters and 2) good long ones cost a lot of money.
If your floor is concrete locate the TT on a stand… or if it is more convenient or you have suspended floors use a wall shelf.