you are still in the construction phase, so nothing is lost - yet!
For the doubts regarding your cooling air flow - have a look at this site:
AutoSpeed - Technology, Efficiency, Performance
Somewhere in there are all the details how to measure your low and high pressure areas!!
Read through this:
AutoSpeed - Siting Cold Air Intakes
AutoSpeed - Eliminating Negative Boost - Part 5
AutoSpeed - We Have a Record!
AutoSpeed - Undertrays, Spoiler & Bonnet Vents, Part 3
AutoSpeed - Building and Testing an Airbox
[...if the posted article is one of a series, the other parts are usually mentioned in the article or search for it on his site! I have a load of the mentioned Magnehelic pressure gauges myself - you find them on ebay for REALLY cheap, just make sure you get the right measuring range!]
WARNING!! ....the above mentioned site is ADDICTIVE!! You might end up NOT doing much on your bus for a while!
He has a lot of mechanical, electrical, electronic stuff there - mostly DIY car improvements beyond what you imagine - ALL of this can be scaled up to buses!
Also - when it comes to cooling airflow - there are a few EXCELLENT books out there about Fluid dynamic cooling - maybe your local library still has copies.
Most of them are full with formulas - don't worry, just read a LITTLE into the text and look at the illustrations and you get enough idea of it all! You mostly DON'T need the formulas as you only will copy "as best as you can" anyway - with your available space.
But I can tell you, you WILL/would make HUGE improvements over the OEM design, by just folling the very basic design rules from these books! It seems the manufacturers don't give a damn about this and just replace smart design with bigger radiators and bigger fans!
A big fan can eat TONS of power - 40-50 hp is nothing going into the fan only!
So if you can reduce the need for the fan running - you start to safe fuel immediately!
Just doing a little research - applying the learned common sense and maybe you have a chance to run a few pressure tests (google: autospeed.com, Magnehelic) on some running bus (maybe your friendly neighborhood schoolbus mechanics takes you along on a test drive and lets you stick a few 1/4" clear tubing on it.....to measure where you get what pressure at what speed....)
Again - WARNING - autospeed.com is seriously addictive to DIYers!!
Looking again at your new Intercooler-auxiliary-"intakes" I get more and more the feeling they actually will pull the air out at this location. You see, the negative scoops are rather large compared to the hoses - this is a rather big area creating a negative pressure.
If you are decided to stick with this location - look up NACA duct intake!!
BUT - beware of "False NACA ducts" - you need to build it correctly or it won't work!!
There plenty of Aftermarket plastic crap out there for looks only, possibly even harming performance. IF built correctly they DO work - key is: built them correctly!!
Enjoying your thread a lot!
PS: What do you mean you don't have the skills for a roof raise and/or slide-outs?!!
Of course you do!!
Have a look at:
and of course Vlad's MACHINE!!
[Although Vlad seem to be MIA, I am sure he will be back eventually...]
Also this one is a good one:
"Raising the Roof" is really not a big deal anymore, more like becoming the rule - and for a MAD MAX, man!! Think it over!