The focuser is also what gives me headaches right now. I have a tube with a lightweight 1.25" R&P focuser for testing purposes more or less ready, but if the objective turns out to be really good (what I hope, of course) I'd like to build a tube with a more substantial focuser, so I can use modern, heavier accesories without problems.
I did some calculations and interestingly enough, you actually need a 2" focuser on it (or at least a M44), if you want the maximum exit pupil with moderately wide-field eyepieces. This is logical, of course, since the f/ratio is 10.4, but it seems counterintuitive, because the scope is so physically small. If you want an AFOV of ~68°, the lowest magnification is 22.5x and the TFOV is 3° with a 2.22mm exit pupil. This is actually WORSE than what the 63/840 can do with a 2" 40mm 68° eyepiece that will yield 21x, 3.24° and a 3mm exit pupil! So if you decide to stay with a 1.25" focuser, you're not getting a wider field than the 63mm and the view is going to be considerably fainter, too. You can brighten the field (enlarging the exit pupil) by using longer focal length eyepieces, for example a 40mm for 13.5x and a 3.7mm exit pupil, but the TFOV is still just 3°. A 2" is going to widen that to 5° at the same power with a 40mm ES68, for example.
Now, the obvious question is of course whether you NEED that extra field. 3° is nothing to sneeze at and hauling the big eyepieces around on a vacation, where you have to travel light, is of course not going to work well - or at all. From home, things might look different, however, especially on deep-sky. On most occasions, 1.25" might be preferable, though, simply because of the weight issues with such a tiny scope.
But finding a quality focuser for a decent price is actually MUCH, MUCH easier if you choose a 2"! I had a very hard time finding a good quality 1.25" focuser. The obvious problem is of course that a 2" crayford or R&P is BIG. I've found a 2" helical focuser that is not much bigger than the M44 helical focuser, but it only has 30mm's of travel, which is short for a refractor and may necessitate an additional drawtube.
Nothing's decided, of course.
And then there's the question of finderscope or not, to further complicate things. Before you say "it's too short to need one", I've actually often found myself wanting one on scopes with even shorter focal length. I'm thinking something like a 4x25 with RACI diagonal. This is because if the scope is used on a low tripod, getting low enough to aim along the scope or use a red dot finder (which I despise, BTW) or a straight through finder can get very awkward or downright impossible.
All of this is merely dreaming and future planning, of course. I do have a more important project right now, which is to get my 125mm f/14 Lichtenknecker up and running.