This is the problem I have with the rosary–if I mediate on the rosary, I can’t think about the words I am saying to Mary, or vice-versa. Focusing on the mysteries causes my Hail Mary’s to be empty prayer. Or if I focus on the Hail Mary’s, there is no meditation going on of the Mysteries.
The answer to your problem is actually very simple. You don’t have to meditate and make the vocal prayer simultaneously.

In your instance I would suggest you announce the mystery (vocally or mentally) such as “The Second Sorrowful Mystery, The Scourging of Jesus.” Then stop and meditate a little on the mystery. Then, after your pause to meditate, recite the vocal prayers such as the Hail Mary. Rinse and repeat. Focus entirely on the meditation and then focus entirely on the vocal prayer. There’s nothing wrong with this at all and in fact it’s one of the suggestions found in an old, old book on how to pray the rosary.
The fruit of meditation isn’t so much how long you spend in prayer. Nor how well you can visualise the scene of the mystery you’re meditating on. If you make use of visualisations at all (remember there’s more methods of meditation than the Ignatian). I very much like the Teresian method. The principle ingredient of the Carmelite method is in the colloquy, the loving conversation that occures between the soul and God, God and the soul, that exists to excite the WILL to acts of love.
Taking the above example of the second sorrowful mystery. If you wish, briefly visualise the scene of the scourging. Don’t get too deep into it, as it’s simply an aid. A faint outline of the scourging is all that’s necessary, and even then, visualisation is only if you need it or not, some do, some don’t. Then consider what it is. Who is collapsed on the ground, chained to a pillar, His back an utter shredded ruin? Why is He there? For what was the Most Precious Blood spilled? Again make it brief or as long as necessary to give you points for the colloquy, the loving conversation. Build the conversation, the actual communication between you and God, on a point you’ve received from your brief thoughts on what’s going on. Express your confusion as to why your God is laying in a bloody mess against a pillar, your love for Him that He would do this for you, your contrition for the fact that your sins put Him there, etc. And it’s good to have resolutions, especially practical ones, to take away as a fruit from your meditation. You’ve just meditated on the scourging, perhaps you’ve resolved to bodily mortification, don’t just leave it as a general resolution, but something solid. Offer up the sacrifice of fasting, or denying yourself television for the day, etc.
And then, after your meditation, say your Our Father, ten Hail Mary, your Glory Be and the O my Jesus prayer. And then move on to the next mystery.
It’s not easy, you need to persevere. Just remember that you’re not after an emotional response in prayer. It’s all in the will.