Identify the job suet must do in your recipe (firm structure, tender crumb, or flaky layers).
Choose a substitute from the table using the texture goal: firm (lard/shortening), fat-but-water (cold butter), or plant fat (coconut oil).
Measure by the listed ratio and keep the fat cold when you need flakiness (grate/cube and chill 10–15 minutes).
If your substitute is softer at room temp (butter/coconut oil), re-chill before baking and watch browning to avoid early melting.
Do a quick crumb check: if the bake looks greasy or collapses, reduce the next swap by ~10–20% or increase chilling time.