I run a Glamorca GP03 wavemaker in my 3’ tank - RSR 250, mixed reef SPS/LPS with a sand bottom. This is a 11,000 LPH wavemaker and the maximum I run my wavemaker at is 70%, mostly lower.
The Reefwave 25 is rated at 7,500 LPH, so probably sufficient. The Reefwave 45 is rated at 15,000 LPH and you would never want that much flow IMHO.
I would personally think the quality of the Reefwave is better than my Glamorca so you would get more ‘bang for your buck’. I would go with the 25 myself. You will get some dead spots on the side it is mounted so you could use an MP10 or a small Tunze if they bother you, will give you more flexibility than a larger RW45.