1. with press-on solids, the tire manfunfacturer can give you foot print area of either standard compound, or non marking compounds which are ~15% softer than std. black compound tires. You will need to provide axle ratings with & with outloads. The drive tires see a higher loadign with a load adn teh steer tires w/o a load.
2. There are some pneumatic (air style vs solid molded) tires - that will go as high as 125 psi in pneuamtic (like single wide profile tires). Most out door truck are soldi with solid molded ( no flats & a 125 psi air line can be difficult to find) - some odl plants have 80 psi in plant air lines for safety concerns.
3. Vehicle CG and axle loadings, if published & not so many do any more - Hyster was the only make that used to give CG location on their lifts but that was long ago) are generally with a standard unit, two stage mast & 42" std. forks and these specs will vary from make to make (all lift trucks are not alike, unlike what some ladies say about men). The sales rep will need to get in contact with the factory to get the info & this may take some, especially if it is not a current production unit it may take some time, as the "engineers (design type no service) aren't too fast to respond & they want "details: too. So be ready w/ make model & s/n & configuration - mast, attachmetents, tire make & size, compund, etc.
This may sound like over kill but as they say "been there & done that" more than just a couple times.