Logbooks are an interesting blend of personal and professional recordkeeping. The FAA doesn't really make a big deal about what method you use to log your flight time, just as long as you log all flight time which you're going to later use to justify currency or a new certificate.
This means that you can do whatever works best for you, as long as you (and your future employers) are happy with it.
When I transitioned to Safelog, I decided to spend a few weeks worth of evenings and just enter everything, line by line. I did this because I had a lot of spare time, and because from now on I've got a pristine digital copy of everything, which is a nice feeling.
However, this is certainly not necessary, and there is no reason why you couldn't summarize your totals with one or a few line items. In fact, Safelog provides a function to do exactly that: you create a pseudo-aircraft type which is defined as "summarizes several aircraft".
You can get as coarse (1,302 hours in airplanes) or as fine (389 hours in blue C-172M's with the funny starter that sounds like you just dropped a shot glass in a garbage disposal) as you want.
I would say that whatever you choose to do, just be sure that you enter it using a format which will be compatible when you switch from Android to iPad. It's bad enough to do it once, why put yourself through the hassle of doing it twice?