Varying sizes in a column - effect?

[EricTheRed]

Hi

So following on from my question yesterday (being true vertical), i have another regarding difference sizes of column in the same setup

the setup
* 30 Litre boiler with domed lid
* 2" bulkhead adaptor - with a 38mm opening
* 2" to 3" adaptor (not packed)
* 70cm 3" Column
* 3" to 2" adaptor (not packed)
* 90cm 2" column (only in reflux mode)
* 2" deflag (only in reflux mode)
* 2" 90° (x 2)
* 60cm 2" shotgun condensor
* 2" to 1/2" copper adaptor
* 1/2 copper pipe to collection jars

Now, the questions are these
a) will the mix of sizes have a detrimental effect on the process?
b) will there be undesirable turbulence as the sizes change?
c) should the larger 3" be after the 2"?
d) should i pack the adaptors as well? They are about 10cm long with most of it 3" diameter

I used to run a 2" packed column/riser in pot mode - but switched to 3" - and my ABV has gone up as a result of that.
I run it as above in reflux mode

ABV on spirit runs - pot mode, only 3" riser - starts at around 88% for about 3 - 4 litres, then slowly starts to drop