Condition of your gun looks good from what I can see.
ML is addictive. I was shooting this one today. A 10 bore by Bales of Ipswich.
[Linked Image from i.imgur.com]
Square loads are very convenient. One dipper for both powder and shot. A 3/4 oz load will be a little more gentle on the wrist of your antique stock than a 1 oz, so there's that. For clays, I shoot 1 oz in my 10.