I use a snow ski goggle anti fog cloth. Works great. I also have used just plain old spray car wax, wipe with the back of piece of old sweat shirt or sweat pant cotton cloth or a microfiber detailing towel.
I have to wear glasses, and a product I have used for over 20 years for motorcycling as well as down hill skiing that is very good is made by a company called Zooke, and you can go to their web site to take a look, order it: https://www.zooke.com/
I use the drip product, rub it on with a finger, polish off.
As far as packable rain gear, I either take my Tour Master step in one piece (the FASTEST to get on and off, and it is 100% waterproof), or I have a two piece suit, the pants are by one maker, the jacket from another. Either Tour Master, or I would have to check to see if it is someone else. I used to use a Fieldsheer two piece and it was very good too, it just got too old.
I agree with the post stating if you can afford it, the waterproof fabric riding suits are the most versatile set up to use. I like Aero-Stitch, but they are extremely expensive. Tour Master (as you can see, I have had very good experiences with their stuff) has some jackets that have removable liners and good ventilation, are breathable and are supposed to be water proof. The problem I have with the fabric stuff is that I am a leather and body armor rider. Probably because I used to road race motorcycles and I know that is the best abrasion protection in a high speed crash. So I prefer to pack the outerwear like the Tour Master step in or the two pieces, and choose when to wear them, and remove them at my first opportunity, because the one downside to packed outerwear is they are all not very breathable and you will sweat in them if the temperature is above about 55 degrees.