I don't think it will stuff you round to much.
It will be easier when you have matching hoops and might take a little bit of getting use to but should be fine.
Also you should check out the multi hooping group there is lots of good info on there.
Before I got the internet in my home, I would use the average hoopnotica hula hoop with a led from trick concepts. It was hard, but handy caps make you better. I got a second led from trick concepts so I could have twins. Much better to dance with. Yet, I'd have to say my favorite pair of hula hoops are hand made by me. they are the perfect size because I sized them. I even started playing with three. So I know buying tape is hard, but the best twin sets are hand made.
It will feel different when you have matching hoops, but not so much that you'll have to start over.
It's amazing what muscle memory will do for you, so when you drill your moves, alternate position of the hoops (and direction of spin), so you don't get stuck with being able to only do tricks if the smaller hoop is on top, in your right hand, in your dominant current, etc.
I sometimes poi hoop with one mini and one regular hoop, so you definitely are able to use different sizes. For on body hooping the timing will be trickier, but definitely workable. I agree with Tink, you should switch out which ones you use on each body part, and you'll be good to go.
I think you are actually helping yourself! Using two different sizes is much harder, but will require you to really focus in on the different movements from each hoop. Mulit-hooping depends on being able to coordinate two sections of the body at the same time, and with the noticeable difference in the hoop sizes, your body will be able to notice the differences more quickly. It may be harder, but I believe it will help you more in the end actually :)
I think you'll be fine when you switch to hoops the same size and weight. You could also try making the most of it and work with the heavier hoop in your non- dominate arm to build strength. :)