I agree with Needsize, I've found that I get plenty of lower pec development from flat bench. I hardly ever do declines, and only occasionally do dips, and yet my lower pecs are probably the best part of my chest.
So I wouldn't worry about not being able to decline. Stick with flat bench and inclines, and your chest will do fine.
Triset
- flat bench 8 reps
- standing cable cros 8 reps
- wide dips with bodyweight until failure
Something definately sucks about the cable cross for me, only the last quarter of the motion i really feel the pecs squuezing. Somewhere i lose tension and or the stress is tranferred to lats and arms....
Really i wish that i could setup two triceps pressdown machines in one line at close distance and do standing cable pressdowns with them