Good to see you're back in der Pool and ready to get stuck in to the work again, though! :)
Tightest radius for a path - I suppose you mean to use 200x100 blocks, laid 100mm wide. If so, and if we are willing to accept joints up to 10mm, then each block can be rotated by approx 4 degrees, which gives a radius of approx 2.9m.
Once the radius comes down to 1.7m, though, the joint width opens to 16mm, as shown in the drawing below. I've allowed for a 3mm joint at the 'tight' end of the joint, and there will be some variation on site, but generally, any curve faster than 3m radius needs to have at least some of the blocks taper cut.
Allowing a 3m radius, if the two 'legs' of the horseshoe can be kept 6m apart, then you'll have only a few cuts, ie, those required to prevent alignment of joints in adjacent courses.