I used only the wheel, bearings and the nylon spacer(between the bearings) from the openbuilds packs. I didn’t shim them beyond the original aluminium spacer because the shafts on my motors aren’t the longest. Although I may shim them by 1 washer if the alignment doesn’t work out. You can see what I’m talking about here in my build log. I am using Phills belt clips and there’s a slight plane difference near the front of the gantry(I don’t think it’s an issue but if I knew about it while I was putting it together I’d have just thrown the extra washer on it.
So Screw->carriage->aluminum spacer->(optional additional washer)->idler assembly->washer->nylon nut works with a 35mm screw. A 30mm cuts it close. I only used these 40mm because I didn’t have any other 35mm(hence the nylon spacer you see).
The potential additional washer would go on the side of the aluminum spacer.
The additional spacer would prevent this slight angle but for me it’s only this way due to short motor shaft. Since you have the 269oz, you have plenty of shaft to move you gear out and in turn shimming your pulleys the additional 1mm
