Yes, you can handle your own dog. I handle Nikon (but I do have my husband or a close friend who he likes "call" him for me if I need it). If you are handling without a double handler then your dog needs to be trained to move WAY out ahead of you and move fast.
A dog can compete as few or as many times as you want. You don't need to earn points or majors or wins; the dog earns a rating and critique every time. One reason a dog can V once and then SG is because judges have bias and/or are willing to overlook things. Like if a dog is obviously too large, one judge may still give it a V rating but another might be a stickler for size. One judge might be "working line friendly" and V rate a nice WL but another judge might be a jerk that only likes WGSL. Getting an SG rating after a V rating does not mitigate the V rating.
Liesje & the K9s
Nikon (GSD) U-CH SG Alta-Tollhaus Bono SchH1 KKL T1 FO PA TF-III FDCh-S CL1-R UJJ U-CA HIT TT CGC
Coke (All-American) VPC's Coca-Cola CGC, couch warmer extraordinaire
Indy (All-American) Blue Horizon's Indigo Girl, flyball star in training
Rainbow Bridge Kenya (GSD) U-CH Alta-Tollhaus-Krieger Lamb Chop CL1-R CL1-F RA HIT TDI TT CGC
vom Blauen Horizont / Blue Horizon GSDs