Harrelson also makes a modular kit:
This would be ideal for a beginner from a performance perspective, however not a great beginning from the financial perspective. It is truly amazing how the combinations of throat (third row in kit) and back bore selections (forth row in kit) really reduce the resistance of the mouthpiece once inserted in the horn, making the play so much easier. In addition are the varieties of cups and rims that grune picture above. In addition, the Harrelson modular also contains nuts (Top row above throats) that fill the gap from the back of the mouthpiece to the leadpipe of the horn.