Does your coach have any input? Kinzie's closet lists a very similar description to the pattern 99 (including the 27" spin rocker) but that information does NOT appear on any of Riedell/Eclipse materials so I don't know how similar the Infinity really is to the Pattern 99 aside from the pick configuration but I've known a few people that had a lot of trouble with spinning on the 99's since that blade has a flatter spin rocker than most other blades pushing the sweet spot away from the drag pick (which may work fine for some skaters, but also seems to cause lots of problems for others - Visions are more widely used at my rink because the picks are a very similar configuration to the 99 but the spin rocker is rounder like most other MK blades and doesn't cause as many issues). I only mention it because you say you are behind in spins, so if the blade profile of the Eclipse is really more like the 99's it might be a consideration that you should discuss with your coach in addition to your fitter. It may not be a problem for you, but it helps to be aware that it could be.
A lot of coaches like gold seals because the spin rocker definitely isn't flat - it has quite a curve to it over a short area (GS uses a 12" spin rocker radius) and it usually makes for better/faster spins and better edge jump take offs, which could make the Pinnacle a better choice, but there is nothing in the description of the Pinnacle to confirm it has the same spin rocker as the gold seal. I'd ask the fitter about this as well.
Either should be a good option though - the information I have about the 99's is somewhat anecdotal, I've never tried them myself, but the people I do know who have, haven't adjusted well. My coach isn't a fan of them either - she prefers the MK Vision.