I agree, the stock single speed works perfectly well. The tension does need occasional adjustment especially for heavier accessories, which is an easy tightening or loosening by hand. When we talk 'stock' here, we mean very high quality, precision & very well baffled !
Its a beautiful OTA, in that its minimal and also both aesthetically & ergonomically outstanding. Like John I wanted to keep things as 'stock' as possible but have made a few changes recently. The visual back is now a 2" Baader ClickLock M64, a Baader ClickLock 47mm Extension slotted onto that achieved the extra back-focus needed for my 3 EP's to work. Finally I am waiting on a Baader M48 to replace the brass compression ring clamp on the EP side of the diagonal. I found through experimenting with different EP's, diagonals (prisms & mirrors), it could get complicated. For one: The travel distances of the draw tube to gain focus with different EP's could be extreme, and in some cases out of range! The 3 EP's i have now all reach focus within mm's of one another, making it simple in use. The ClickLock system makes it easy to twist and shout (so to speak). The thing is once you start with this stuff everything else has to step up to the mark too, so if there is a small part of the setup that is the weakest link I feel a compulsion to try and iron it out until the whole works seamlessly. That said, I would add an MEF-3 as the last thing, it is the stronger part of the set up in my opinion.