I had some good games with Benteke as a DLF at the top of a 4-2-3-1. He ran the show at Old Trafford for example, scoring 2 and setting up Tom Ince for the third in a thrilling 3-2 victory. But Wiemann as a ADF is also a good prospect so I'd suggest getting as much as you can for Bent and reinvesting.
I sold off Bent (£16m), N'Zogbia (£6.5m), Ireland (£5m), Bannan (£3.5m), Given (£300k) and Lichaj (£350k) and got rid of a few on loans (Hutton, Herd, Westwood etc.) That gave me around £30m with the budget adjusted to £150k p/w
Unfortuntaly my game keeps crashing so I'm struggling to get far, but Tom Ince (£7m), Vincent Wanyama (£6.25M) and Jack Cork (£5m) were expensive but doing well for me. Delph and Gardner played well in the AMC position.
Jonathan (From Inter) and Diego Contento are available on loan and are both very good fullbacks, Contento you can get on a loan to buy deal for around £5m.