I have experience lowering the main on the water, not so much raising it. I think I did it once or twice and didn't have troubles but the wind was´t very strong. The challenge is to keep the boat facing into the wind or close. I manually rotate the mast often to have it pointing into the wind if the boat isn't, this is critical, the rotator helps. You have to sail backwards most of the time and eventually forward to correct the angle. Basically you raise the main during the slots of time where the boat direction allows it, and then deal with boat direction again. I've never rolled the jib, I suggest to test with the jib on, it helps keeping and correcting the angle. Some times backwinding it if necessary. You need some room and a crew. If it's tight, then yes, you need an anchor. Waves can make it much harder too. I needed to lower the main on a lake, sometimes I landed on a safer spot just to lower (or raising in your case) the main, that's an option too. I also suggest a
rigging tool like this one, to protect your hands and to be more effective connecting the ring.