[Puster Bill]

I know this might be considered heretical, but why not just go ahead and use a real slide rule instead of a virtual one?

I carry a 6" Pickett N200ES Trig linear rule for when I need to be 'discrete' about playing (I use a laptop), otherwise I use Hitman's wheel (a physical version).

I picked the Pickett up on Ebay for a reasonable amount. I also have a plastic Sterling I got for $5 at an antique store.

Sometimes I even plot contacts on paper using a cheap ruler and protractor I bought.

Using a virtual slide rule is like kissing your sister: The motions might be the same, but it certainly doesn't feel the same.