Hey Globi,
Good questions... and I understand your agreement...
I use big fonts because I've only one good eye... and it goes on the blink all too often making reading difficult at best. If you'll check, I use the same large font in all my posts... That's so I can preview and proof them before I post... I find this lot easier and less time consuming than zooming in and out on the small drafting window.
And please forgive me for not remembering you live in or near the flatland part of the BENELUX where most of the tulips grow and a lot of land is below sea level and you can still see some of the classic old wooden wind mills.
As I recall, they sell some the finest grades of sensimilla from Canadian Northern Lights to Maui Wowie paca lolo on most street corners along with slabs of primo hash thick as shoe leather, but finding over the counter stuff like vitamins and minerals can be difficult at best if you don't speak the lingo and then the selection can be limited...
You're correct, 250 µg cholecalciferol (vitamin D3) is equal to 10,000 International Units (I.U.) so in the case of vitamin D3, the conversion factor is 1 µg = 40 I.U.
Marta had a similar problem in Switzerland trying to obtain the 5,000 IU liquid softgels of vitamin D3 and calcium citrate tablets formulated with the cofactor minerals for Michael, so she ordered them over the Internet and had them in less than a week.
The following graphic illustrates the time course serum 25(OH)D response to dose of vitamin D3.
As you can see, it's going to take a dose of 10,000 IU/day vitamin D3 to get your 25(OH)D level into the green zone in a reasonable period of time where the odds are you'll have a favorable response to the anti-inflammatory regimen.
Of course, that's if or when the ONS trial coordinator gives you a green light to try this regimen.
I think it would be difficult for them to refuse you treatment for a seemingly unrelated vitamin deficiency unless they're reading this thread or they've been following posts on the anti-inflammatory regimen...
Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

This green zone was defined by 70 of the 100 CH'ers who tried this regimen and experienced a pain free response or had a significant reduction in the frequency and severity of their CH. Many of them posted their 25(OH)D lab test results and all were ≥ 60 ng/mL, (150 nmol/L).
CH'ers with active CH who have gone in for this test and all were ≤ 42 ng/mL, (105 nmol/L), the upper boundary of the red zone.
IFB, your weekly dose of 50,000 I.U. vitamin D3 will work. However, if you interpolate between the 5,000 and 10,000 IU/day vitamin D3 dose response curves, you'll see that it's going to take nearly 3 weeks longer at your present average dose of 7,142 IU/day than it would at a dose of 10,000 IU/day to get your concentration of 25(OH)D up to 60 ng/mL.
Of course that depends on your level of 25(OH)D when you started supplementing with vitamin D3. The response curves above used a starting concentration of 25(OH)D of 26 ng/mL.
Globi, as a side note... I used to fly into Schiphol to attend conferences at the SHAPE Technical Centre, Den Haag, usually to watch how they tried to cook up a soup sandwich of interoperability standards for NATO. A thankless task... but needed.
My favorite stomping grounds while there was out in Scheveningen. There were some fine little restaurants near the Het Kurhaus. On one trip, the staff at the Technical Centre hauled three busloads of us out to Maastricht to eat at a restaurant called Der Mol.
It had a medieval theme. The waiters and waitresses dressed in the same theme with bizarre facial prosthetics, masks and theatrical makeup.
All the food was served by candle light without flatware, so had to be eaten with the hands, except for the soup that came with a wooden spoon you could take home as a souvenir. At times between courses of the meal, the waiters and waitresses would break out in theatrical productions and song. It was a hoot!
Joyce and I went back to Masstricht a year later with another couple from the UK to find the restaurant, but it had evidently closed and gone out of business.
Take care and again, I wish you all the best with the ONS implant.
V/R, Batch