I understand that you want to buy some clamps, and I would still say pipe clamps are a good alternative to sash clamps. However, I will also push the home made again, as these builds are really not complicated.
For small panels, using wedges is a very good alternative, and helps to spread the force more evenly. Google ‘Wedge Clamping Jig’ to see what I mean. If you have prepared the edges well, you don’t need a lot of force to get a good joint.
That same search will also start you off on home made longer clamps as well as other ways to glue frame and panel doors etc. It’s very rewarding building these things, and it builds problem solving skills too.
Colin, Czech Rep.