Fillet Gauges are fillet Gauges.  If you need to know the type, you may have a problem .  If you can not work with ANY gauge, save your money and don't take the examination.  Just be sure that you know how to use all the instruments.  Remember to read and understand the acceptance criteria.  Remember to apply the stated acceptance criteria when you answer the question.  Practice, Practice, Practice.  Read that imitation code book you get with the examination notification pack.  That code book is what will be used in the actual examination.  You can improve your speed if you knew how to use each of the tables.  But do not try to memorize the tables, look up the answers when you take the test.  I would urge you to beg, borrow or steal the money you need to take that course.  You sound like you need the confidence you would get from taking that one day course.

As for buying tools before hand;  I would have assumed you had been using these gaugers all along during the "Experience" phase of your career.  If you haven't used things like fillet gauges,
V-Wac Gauge, ruler, Etc., what kind of experience do you have inspecting?

also remember if you find multiple references in the index to a topic within a single chapter to check both the text and table, the table may well have a footnote that renders the text answer inadequate.

i agree with johnnyh. no need to memorize anything. just make sure you know the layout of the code and how to find things quickly. i tabed the main tables and sections. and always read the notes. i'm sure you've heard this all before, sounds like you'll do fine

A good number of people have trouble with the practical examination. It isn't universal as to which portion of the exam is the most difficult.

Some people have difficulty with the mathematics. A firm foundation in algebra is not required, but it is helpful to be able to look at a formula and be able to apply it to a problem. You will be required to calculate the area of a circle and rectangle, convert customary units to metric units and vice versa. You will need to be able to convert fractions to decimal and decimal to fractions. You will have to add and subtract fractions. Converting fractions to decimals will require you to "round-off" numbers and you will need a basic understanding of significant figures.

Other people have difficulty using the gages and measuring devices provided for the examination. You will not be allowed to use your own personal fillet gages, micrometer, calipers, etc. for the examination. As simple as measuring a fillet weld is, there are some basic concepts that people forget when they enter the examination room. Joe recommended taking the seminar if you are not familiar with the proper use of fillet gages as well as the use of a micrometer and dial caliper. That was sound advice. Joe may not sugar coat his answers, but they are always on the mark. There are several questions based on being able to use traditional (non-digital) measuring devices. You will use those measurements to calculate several things such as cross sectional area, ultimate tensile strength, etc. Some of the answers will involve converting metric units to customary units because both may be listed as answers and both the metric and customary unit answers may be correct.

The Practical Examination requires you to use a welding standard that is a composite of several industry based codes. The candidate has to be able to divorce himself (or herself) from the code they are familiar with and apply the criteria contained in the composite standard provided. In some cases, the requirements run contrary to the requirements of the code you are familiar with. Answering the questions based on the actual code you use every day (real life) will result in the wrong answer being marked on the answer sheet. This portion of the examination catches people off guard because it requires you to apply a standard that you are unfamiliar with. The common refrain I've heard is, "I don't care what the standard says, I won't accept that weld!" That is the attitude that will cause a candidate to fail the examination. A weld that should be rejected by nature is, by the standard, acceptable or vice versa.

Good luck and study, practice, and study some more.

Best regards - Al