Take a look at what is being used at the next match. Also look at the magazine carriers.
For your first match, you could probably get by with an Uncle Mike's with the strap removed.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)