|When I use a pattern that has different lengths on the same pattern piece, I cut along the line indicated for the shorter length then abut the two pieces back together and tape vertically every 2-3 inches across the cut, joining the two pieces back together. This allows me to lift the bottom section up to get an accurate cutting line for the shorter length and keeps me from losing the cut-off section or having to lift up the pattern to make the cut.
I use paper tape instead of regular tape. It can be ironed over without melting. It is found in the "bandaid" section of almost any store. It used to come in wide and narrow widths but lately all I've found is the 1 inch size. I cut it across in 1/2" inch pieces. If I need a longer length, I cut off 2-3 inches and cut vertically into narrow strips. It is also great for mending patterns.