Which would be best? Using a sleek and slim race style seat or a bigger bulkier seat?

Saddles are personal preference. Find a shop that has a good return policy or a demo saddle library. Also, you don't want an overly cushioned saddle. A good saddle will support you by your sit bones, and a saddle that's too cushiony will cause you to ""sink"" into it, putting pressure on your perineum instead, pinching nerves and cutting off circulation causing the numbness.