I get 8 (any size, any type) "covered" - until my deductible is paid out, I still pay 100%.
Anyway, to cutting - I have a small cutter box from a real pharmacy (the ones that depend on pharmacy as a business, rather than the corner of the big box store) that helps you position the pill. The 20mg is the same shape, much larger, but the challenge remains.
I cut first across the narrower width, then cut the "halves". Clearly this is not a balanced quantity, but since I cut up several at a time, and put them in daily pill boxes, I just use a best visual guess at arranging them in order to balance the dose. Smallest piece one day, larger the next.
Since Cialis builds up for a few days in your system, the scheme does not have to be even close to perfect. There are a few times that I really mess one up. Put the fragments aside and take those one day.