I'm going to make a meatloaf layer cake for a birthday party. I don't make this often but every time, no matter how careful I am w/ the mashed potatoes, there are some lumps and it gets caught in the pastry bag tip. It's a pain because you have to take it apart, hot potatoes in the bag, and remove it, continue. It's messy and time consuming. Recipes I see online use instant. It seems like it would be much easier. I vaguely remember having samples at Costco that weren't bad at some point but can't remember the brand. I thought it was just potatoes, salt. Is there a good one? If not, I'll go back to making my own. Thanks!