Thanks for your comments mate.
I have a 1.75” Colt which tapers to 1.5” at about 7” and this hurts because I squash the head and the table will show an area of 1.77”.
But a straight wall oval 1.5x2.0” oval has an area of 2.36”.
I have done these calculations based on the surface area.
An ellipse surface area is Pi*a*b. This gives a more useful comparison than circumference.
I have decided to try the vacutech 1.5x2.0” oval to give more length stretch.
Type Cylinder Size Radius a Radius b Area
Vacutech 1.25x1.75” oval 0.625 0.875 1.718
Straight 1.50” cylinder 0.750 0.750 1.767
LA pump 1.5x1.875” oval 0.750 0.938 2.209
Vacutech 1.5x2.0” oval 0.750 1.000 2.356
Straight 1.75” cylinder 0.875 0.875 2.405
LA pump 1.75x2.125” oval 0.875 1.108 3.044
Vacutech 1.75x2.25” oval 0.875 1.125 3.093
Straight 2.00” cylinder 1.000 1.000 3.142
LA pump 2.0x2.375” oval 1.000 1.188 3.731
Vacutech 2.0x2.5” oval 1.000 1.250 3.927
Straight 2.25” cylinder 1.125 1.125 3.976
Vacutech 2.25x2.75” oval 1.125 1.375 4.860
LA pump 2.25x2.75” oval 1.125 1.375 4.860
Straight 2.50” cylinder 1.250 1.250 4.909
LA pump 2.5x2.875” oval 1.250 1.438 5.645
Straight 2.75” cylinder 1.375 1.375 5.940
Starting 5.9" x 5.0 (BPEL x G) .. Current 7.0" x 6.0
Goal 7.5" x 6.5"