IMO, save it for a last resort. simplest way to increase calories is to increase serving sizes. extra chicken breast here, extra peanut butter there, etc
if thats not possible, you can buy a big container of oats and some protein powder and make your own. many grind up the oats and put them in a shaker cup, then add either bananas and vanilla protein powder. or cappucino and chocolate protein powder. or even strawberries and strawberry protein powder.
then as a source of fat, you could do olive oil or flax oil or peanut or almond butter.
shoot, some just take a glass of milk and add milk powder and peanut butter and ice cream.
if none of that is possible, HWG 900 is fine.
