The OP's starter is a Sullivan Dynatron which is a 24 volt starter system and a five cell lipo is going to be what something less than 19 volts? Decidedly lethargic. Any battery chemistry that is going to be less than 24 Volts is going to be disappointing for the bigger stuff and certainly not insane.

The Black an Decker makes a heck of a lot of sense for the Dynatrons and boy do they work , yes they are Nicd's and yes you need to charge them every time you go out (I would not do otherwise with any battery system). And they are reliively cheap you do not have to deal with assembly of a bunch of loose cells and if ya don't have the drill then just pick up the B&D charger or like I do use one of my two Venom Plus chargers which I charge just about everything with and are rated for 20 cells or 24 volt.

As far as hand propping of my larger engines, well no thanks although I have done it out of my wheelchair its a challenge but using my appropriate starters it is not.

Yup lots of choices! ain't that Cool

John