Pumpkinpal,my 14yr old Rocky also has HyperT and is on the same amount of meds as your Sampson.
My trick for pilling him,I crush the pill in a soup-spoon add some food and stir it up,Rocky will readily lick it all up.
I do this 3 times a day and after the spoon he gets his dish,raised on a thick book.
Rocky would not eat before I raised his dish,I too feed mine Wellness canned,no dry at all.
I also have 3 cats and they get about 3/4 of a large 12,5 can in the morning,the rest at lunch,then they get a 5,5oz can at night.
Rocky unlike your Sampson,does have a very good appetite,but is not gaining weight,before he was diagnosed with HyperT,he weighed 16lbs and now a skinny 11lbs.
My vet thinks Rocky might either have kidney problems or cancer,his calcium level is too high.
He put Rocky on Prednisone 1 0.5mg pill/day and he'll get some more tests in a few weeks.
I always know how much my cats are eating and who is,I have stainless steel dishes with different color bottoms.
Also if I put any food in the fridge,I put the dish in a bowl of hot water,like Growler said,my cats do not eat cold food from the fridge,I guess they cannot really smell the food if it's too cold.
Rocky drinks a lot of water,always has and I am
he does not have cancer,or kidney-problems.
Good luck with your boy,I know how worrisome it is