4x5 can easily be done in an 8x10 tray. Slip one edge in and push/slide to submerge. Agitation is lifting two adjacent sides 1/2 to 1 inch and lower. Start with top and right. At 15 sec mark, do bottom and left.
I have no idea how to keep time unless you use an audible timer. Cover tray so as not to expose. E6 is a long process, around 45 min for the 6 step. 3 step kits with blix give dull colors. do not use. Been there, done that.
4 sheets will be 3+ hours, painful and a waste of time. Buy or make one of the 4 sheet dividers for 8x10 tray. Use 6 trays to cut down on contamination.
The very worst thing that can happen is backwards contamination . you will never figure what went wrong.
The best process is a Jobo with the revolving drum that hold 10 sheets. Uses 8 oz of chemical.
Best of luck