No problem,
@mellowjamie,
On an unrelated note, I miss the UK I am well aware you Yorkshire men like a bargain so very chuffed you're well pleased !
I agree, to a certain extent, IEMs can be messy & a good fit is paramount so I would suggest don't be afraid to experiment with different tips, perhaps you may be among the rare few which need different sizes in each ear or you may need smaller or bigger than you realise. I also suggest if you haven't seen these around already, try looking into Crystaline Audio tips, they are a UK based company so they should be easy at least, to contact.
Otherwise using IT 01 as an example, Comply 500 fit well & do Spin Fits if you require a potentially odd fit foams may not give you.
One day I should write a help guide on tip selection & the like though it will probably be somewhere else first then archived on Headfi, I will certainly let you know if that happens...
I hate to say but you haven't had the best of luck so far with your IEMs as all the reasons you outlined are pretty much general concensus...
So you should be more than happy with IT 01 when you get them though I would suggest rolling the stock tips if they don't seem right.
In general, a good measure to see how well an IEM/headphone fits &/or sits is to just wear them with no sound playing & see how they feel, if you can be comfortable for at least 10 minutes this way, then you should be good.
Also as a final note on fit, it is important to remember don't shove the tips too hard into your ear, just gently push them in till they can go no further.
Be interested to know how you go, if you have any issues, feel free to PM me if necessary...
Sadly, I agree with you regarding B & O, as they are treated much like Bose, both make decent but all subjectively depends on taste.
I don't mind either though personally & subjectively, it's not something I would choose given the choice but I can certainly appreciate them & wouldn't snub them just because...
I demo as much as possible myself, I believe in a demo for any audio gear, hence why it's in my tag but I digress...
Basically, on stuff unable to be auditioned, it all comes down whether one wants to take a chance or not but good to hear you did take the guantlet, so to speak, it is the only way to know what you & only you will be happy with.
Nice home set up with the Graham Slee, I almost considered them at one stage but they had really limited stock where I am & outside the UK, GS can be pricey for no reason which is why it didn't sell for very long.
Also no demo...
What Hifi is a crock, I am not a fan of pretenious BS & frankly I think most of the reviewers are not only deaf but have no clue how to review any sort of gear, let alone audio gear & there are a lot of things they said were terrible but I thought close to the dogs bollocks or at least very enjoyable.
I am not a fan of pretentious audio idiots by any measure but that's another story & I digress...
Source Synergy with IEM/Headphone/Cable is ridiculously important, glad you like your current set up.
By the way, I believe Pioneer owns or at least has business interests in Onkyo so I am not surprised they are basically rebadged...
Burn in is so subjective & personal & more often than not, when manufacturers recommend the process, it is more to make sure all components are working as they should, if there are any changes, it is usually more subtle than not though there have been few exceptions which are actually obvious.
Sound Perception Bias plays a part but that's a whole other discussion.
In case you're not aware, IT 01 has a recommended burn in/ initial play time of 100 hours to 'settle in'.
IT 01, personally & subjectively has among the best single DD I have come across, that is partly due to the DD being made from Graphene but more just tuned 'correctly' though that is subjective in itself.
You won't be disappointed with the sound.
I am sensitive to high frequencies myself, I have quite a number of songs which actually reach into not just the high frequencies but the higher frequencies & I can tell you there are no issues when they are played through the IT 01.
As before, I suggested Penon GS 849 cable if you want more control over the tuning if the stock cable does not quite suit your tastes but you should be fine.
Balanced Amatures only have a high frequency issue if they are not tuned to a 'neutral' &/or 'balanced' sound though that is hard to say in itself as everyone has different preferences.
If you're curious on what a good BA can do, especially value for the money, I suggest the Audio Technica E 70 (pro audio shops will have good deals on this), was my go to for 3 + years & now semi retired though slowly coming back into my weekly rotation.