Pittman would be best but the 555 with a PTC would be a better choice than a Canon. These at least have a decent track record of not destroying themselves.
I put ERR in a Williams Niagara with a 555 for a local club that has been running it at least hundreds of hours if not thousands with no problems other than tires.
Thats a good Pittman. Its a 61 mm one though so check the space you have. Numbers ending with 33 are 56mm.
Pete