10 speed Shimano cassettes are interchangeable across the board. Only difference I'm aware of are some Easton freehubs which -- for whatever strange reason -- are minutely different and are specifically designed for only dura-ace. But that's a very rare anomaly.
Otherwise, you're doing what I've been doing for years. Train on 105 -- steel cogs, cheaper, longer lasting. Race on Dura Ace. More expensive, lighter and slightly less durable due to Ti cogs vs steel cogs.