skinny at 43....worse problems to have at 43. LOL.
Welcome. Might ask what your typical diet is like to help all around.
On your non-gym days (or whenever you fee like it for that matter), might suggest throwing in some of the cycles from P90X.....max reps, standard/wide/military/diamond push-ups. And some yoga can be a killer core/shoulders workout. For that belly, never had that pooch belly, but also never had that elusive 6-pack of abs. Starting to get there by doing israeli sit-ups, kimora situps and working the heavy bag (www.ckotrainer.com
). Find that the kickboxing workout works abs all around, as opposed to doing a zillion crunches (atleast for me). If don't have or don't want a heavybag, you can order from walmart.com some 4lb weighted gloves. Punching (and/or some Les Mills Combat) with a bag or gloves shredded my back, arms, shoulders and abs. Combo workout because it's cardio + light-weight type workout = endurance, lower bodyfat, lean, useable muscle. This after striving for decades to get 'big' only to findout I had little endurance strength useful in day to day.
My opinion...like lots in life....BALANCE....weights + something else.
I like what Sea Siren said too about limited rest period between exercises. Again, endurance. Real strength vs being able to do 1 rep of max weight 1x. Impressive in the gym, not too practical in real life....