Long-time lurker.
Cialis researchers consider 20mg the maximum occasional dose and 10mg the best dose for those who have health issues of any sort. The approved corresponding daily doses are 5mg or 2.5mg per day.
In my own personal experience - and the experience of others mentioned in threads here, there is no advantage to taking more than what does the job. But there is a health benefit to taking the least amount of supplements that will do the job.
it is a huge survival trait of the human species, that each of our genetic makeups is different from that of others (so that a particular plague does not wipe out everyone).
So, what works for someone else might not work for you. I think that Gene's physiology is very robust, I don't think most people can thrive ingesting that many different substances. (Although we have all gotten a huge amount of helpful information from Gene's posts over the years, thanks!)
In my case, after trying Cialis briefly some years ago, I recently had some ED issues, and so tried 10mg and had several days of headaches (as well as erections

). Next time I tried 5mg and this time only a day and a half of headaches. 2.5mg worked very well and only a little bit of headaches.
Then, with some very careful pill splitting, I tried 1.25mg and have had excellent results in terms of erections - and no side effects. I am currently trying 1.25mg every other day. The first time I tried 1.25mg before the previous dose left my system, the effect was as strong as several times the dose - but no side effects.
My use is different from Gene's stack, but my recommendation is to start with less of a dose, and see if that works. If you then find that a higher dose has benefit for you - great !
But otherwise, note that 5mg costs half as much per month than 10mg, and 2.5mg costs half as much as 5mg - a big advantage for some of us.