I have a 63 vibroverb reissue that needs new speakers. Amp is rated at 35 watts, nominal 4 ohms resistance. I'm thinking of mounting only one JBL E110-8, which has impedence of 8 ohms. This speaker weighs 40 lb. I could mount two and match the 4 ohm nominal impedence of the amp, but amp would weigh over 100 lb. Would using only the one speaker be safe? Would it sound good? Is is necessary for me to somehow put more resistance into the cabinet to match the impedence of the speaker to the nominal resistance suggested for the amp, or is using an 8 ohm speaker with a 4 ohm amp no problem. Thanks for your reply.