The most important instrument to incorporate into your scan on the 757 (I've been flying it for about 3 years) is the IVSI,
So set your pitch attitude on the ILS...at between 1 and 2 degrees (depending on weight)
Set the thrust for flap vref30 + 5 which will be between 1.18EPR and 1.20EPR
and make SMALL adjustments, the key is not to over control, the sim will be a little twitchy..just keep the control inputs small.
As for a non-precision approach to MDA, I would suggest you plan for a constant descent angle..rather than a platform level off.
Good luck