You get the BT vaccine from your vet. It comes in 20ml and 50ml bottles and the dose is 1ml per sheep, given by subcutaneous injection. Once the bottle is opened it has to be used within 8 hours. Your first problem is that you only need 5 mls to do your whole flock. Maybe your vet will be opening a bottle and will be able to give you the 5 doses you need - it's worth asking, otherwise you will be wasting a lot. We had to wait about 4 weeks to get some 20ml bottles but only a day for a 50.
When you speak of a 'rise' in fleece, it usually means the line of weakness in the fibre from the winter, before the new wool starts to grow in - this gradually rises up through the fleece in a line. When you shear, you cut through this line, which needs to be above the skin - for hand shearing 1/4 to 1/2 an inch. Perhaps it doesn't matter so much for machine clipping, but if your shearer says there is no rise then it's probably best to wait until there is. If they are daggy, you can crutch them which will keep flies at bay. Wool insulates in both directions - warm in winter, cool in summer, so they are probably ok if they have some shade and you watch out for flies. We have done about a third of our flock so far - they do look smart
Let us know how you get on.