In my opinion, this contains too much fluff which is uninformative. This isn't a letter for undergraduate admissions. Your letter should succinctly convey information that's pertinent to the admissions process, but might not be readily available in your application package, at first glance. In most cases, this is when you elucidate your exact day-to-day role as an RA (since doing lit review as an RA pales in comparison to model calibration, if we're looking at structural work), if you've done any RA work.
If you lack sufficient math courses on your transcript, use this opportunity to either explain why, or provide assurance of your ability in handling the coursework (preferably, through a good grade in a grad course, which you can briefly detail the syllabus).