I've been riding my 8.10 133 litres mana for a while now ,,and did struggle on a lumpy on shore day ..but still had fun slashing around ,the next day similar conditions ..but a little bigger ,head high .I thought I'd get my 9,6
170 litre Hokua x32 ..dam near broke me ankles off .

.it took me two waves to relies ..it was a big board and walk back to turn it had to be done .got the hang of it ...but I didn't know how much more pressure is on you ,and your joints ,to turn a bigger board ,so going to a smaller board was one of the best things Ive done .I actually thought I could go back and use my older bigger boards ,but I don't even want to go back there ..
i still struggle a bit on my little board in chop ,but the benefits of small boards are sweet.
i have a couple of mates biting at the bit to get their hands on my 9,6 ,time for them to
cough up the bills

i don't think I will ever go back up again .

so if you think you can ride a smaller board go for it .but know you limits .