An upside is that no fee is applied for exceeding your credit as long as you bring it back within your credit limit within a reasonable time. You can only use this card on QVC purchases, and as with many store credit cards, no cash advances or balance transfers are available. Returned payment fee is $29. Late payment fees will depend on the size of your balance, and vary between $15 and $39.
If you may want to set up a Dressage arena inside your regular arena, that requires more length. A small dressage arena is 20X40 meters (or about 66 feet by 132 feet), a large dressage arena is 20X60 meters. A standard size competition arena is about 100'X200' and is large enough for full jump courses and other uses. Also consider the fence material.
somewhere I read that 92% of dressage rides in the US (test rides) are at training level. That includes eventing dressage. I don't think you can go by the one or two big coast shows that has a lot of FEI riders. I think there are very many more riders at Training Level than any other level. There are multiple huge classes at most shows every day for training level.