Have you asked Andy?
In order to avoid posting Andy Baker's program online, I don't want to provide any more detail than necessary. Strength & Mass After 40 ("SM40") is a four day a week 531 variation that utilizes sets of 5 in week 1, sets of 3 in week 2 and singles in week 3. Briefly, on one day there are prescribed sets of incline and decline dumbbell presses. While I can raise one side of the bench without making things too unstable, it's not something that I would do for larger inclines. Should I replace the incline work with additional bench press sets? Similarly, should barbell movements substitute for one arm dumbbell exercises?
Although there are some good adjustable benches, I strongly prefer a flat one for benching. Although I have considered adjustable dumbbells, except for small plates all of my weights are urethane bumpers, which means I would either need to buy a bunch of individual plates or order something like PowerBlock or Bowflex ones. Since most of the programs I have followed have been centered around squat, bench, deadlift and press with a barbell, I haven't felt the urge to add an adjustable bench or dumbbells to my home gym.
Have you asked Andy?
I'd do push ups with feet on bench and dips.
Thank you for the suggestion. Although I sometimes did those as a warmup when waiting for a bench or as a supplemental exercise, they're fairly hard to program. If you want to add weight safely, you will generally need a spotter to put a plate on your back and make sure that it doesn't slip and hit you on the head or your need to use a weighted vest.
My guess is that the simplest solution is just to add additional barbell sets in areas where dumbbells are prescribed and on the occasions that I do go to a gym utilize dumbbells.
I would advise asking Andy as well, I hear he is typically very responsive to those who have purchased his programs and is overall just a friendly guy. While I don't have SM40, I have been running both HLM and HM style programs since I got off my LP and have consumed a fair amount of Andy's content, the man is a damn-near bottomless well of knowledge.
I believe he typically prescribes these styles of exercises as accessory or "pump" work for the main lifts and to provide additional volume to aid in muscle growth, usually in the 3 sets of 8-12 reps range I think. For decline bench, the best solution would be to do dips instead; dips are a similar movement pattern and can provide some excellent assistance work to both the bench and the press. My opinion, they are far safer than the decline bench as well.
To restate, since these are accessories, they are not as important as focusing on the main lifts (Bench and Press) - but for the incline DB press, a barbell incline would be best. You might also try something akin to a landmine press too, but there's a limit as to how much you can load and safely perform the exercise. An incline machine or cable version might suffice too - but again the loading is limited. Honestly it might be best to just add an extra backoff set or two of flat bench. So, for that day it might look like:
Heavy Bench as written + 1 or 2 backoff sets
Light Press
Dips
That's plenty of upper body stimulus if you're lifting heavy enough.
Thank you very much for the detailed response. I wasn't sure how receptive Andy would be to my questions, so I am glad to know that he is both knowledgeable and friendly. You are correct that the exercises I am asking about are all accessories. I have been utilizing Jim Wendler's advanced 531, which is similar to SM40, with the main difference being that it utilizes 5 sets instead of 3 for the primary lifts and 3x5 instead of 5x3 for the secondary lifts. So, I am doing 2 more sets of each primary exercise than SM40 prescribes.
I have always focused on the main lifts and used accessories to attack weaknesses. Since Jim believes that once you hit the advanced stage you should know what assistance you need, I wanted to incorporate some of Andy's ideas. Also, at 64 it helps to consider the advice of those who spend a lot of time coaching older lifters.
I have a flat bench but not an adjustable one. Since my bench has wheels, propping up one end of the bench more than a couple of inches gets dicey. While I have been utilizing dips, I have AC joint issues which are aggravated by them. Although I have gym membership to supplement the missing equipment in my home gym, I don't go there as often due to the mask requirement.
Instead of dumbbells, I am considering buying a multi-grip bar which would may allow a similar range of motion. Also, I would be able to use the urethane bumper plates that I already have.