Yep - if you have an 11 and 14, you could get an 18 or 20 to give you a really good quiver for 70kg.
You dont really need the 16 with only 70 kg - but as BA said - it depends on your actual kite (low end or windrange ?)
The 14 will be your "ideal" kite for many conditions.
If you had a 16, I would go 16-12-8/9 instead, if its medium power kites.
Even though the new 18 and 20's turn much better, they are still "dogs" for 70kg riders particulary...
But with a 16m2 kite you have a really agile kite (if its a new one....), and has almost the same low end - just with much better jumps and handling.
Do you have really consistent low winds a lot, you might be better off with a really big power machine (18-20), and then your 14.
Just my opinion - as here are we really talking opinions, and nothing else
For some reason, many chooses their sizes so they have big steps in the big ones.
I dont - as I prefer to be able to choose the size that is just fully powered, but as small as possible - in medium winds.
When light wind, you just take a huge one (doesnt really matter how big - a huge step could be fine here), and in heavy wind - you take a small one. For me, it does not matter much here.
But in the "critical" zone, where kitesizes really has a dramatic effect on turning speed and agility (from 13 to 17m2 is my critical range), I prefer to have at least two kites.
Luxury - but I still prefer this, as there is nothing worse than not being able to choose a kite small enough, but still being fully powered.
In lighter or heavy winds I dont mind that much - as there is no problems with the small one, and the big one is a "dog" anyway.
It is very different from what most others do, I know.
Or are there anyone else that do the same ?
I can tell you one thing - so many kiters have really deep regrets, because they buy a big kite, and then the next one 5 or 6m2 smaller.
The windranges will just overlap, true - but they are ALWAYS missing the kite in between, and always in doubt what to choose.
This is not so much of a problem when there is really light wind (the big one), or heavy winds (you can always get sufficient power with a small kite because of its speed and turning), as I see it.
So I prefer bigger steps in the "ends" of a quiver - and smaller ones in the medium "critical" area, where kiting REALLY starts to be more fun for every size you go down...
I know it might sound a bit strange
Not more kites - but just distributed different, as my personal experience tell me that this is best for me.
Another thing is the "what if I can afford a kite more" problem.
Having steps of 5-6m2 will make it really bad to put another one in between.
Having smaller steps, you could get a bigger one, or a smaller one.
Or having a really big step (like BA), will make it easy to fill a kite in between.
Just my thoughts, and what I see happening when people buy kites.